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Real's HowTo@www.rgagnon.com1 Applet..............................................................................................................................................1 . 1.1 javaapplet........................................................................................................................1 1.2 Goto to a new URL from an Applet....................................................................................1 1.3 Determine the host from where the Applet is loaded.........................................................3 1.4 Have a scrolling status line................................................................................................3 1.5 Use a search engine..........................................................................................................5 1.6 Have an onscreen clock..................................................................................................6 1.7 Have Applets on the same page communicate with each other........................................8 1.8 Have Applets on different frames communicates with each other.....................................9 1.9 Send a message from an Applet to another Applet on a different page..........................10 1.10 Have an applet launch an other applet..........................................................................12 1.11 Get the user name.........................................................................................................14 1.12 Access parameters passed in the URL ..........................................................................14 1.13 Convert an Applet to Application ....................................................................................16 1.14 Change the mouse cursor in Applet..............................................................................17 . 1.15 Use an Image as the Applet background.......................................................................17 1.16 Handle the new Control Activation mechanism in IE.....................................................18 1.16.1 Solution #1............................................................................................................19 1.16.2 Solution #2............................................................................................................19 1.16.3 Solution #3............................................................................................................20 1.17 Pass parameters to the Applet JVM (WIN)....................................................................21 1.18 See the Java Console Window Log (Java plugin).........................................................22 1.19 Display debugging infos for an Applet...........................................................................23 1.20 Have an invisible Applet................................................................................................23 . 2 Date and Time...............................................................................................................................24 2.1 javadate.........................................................................................................................24 2.2 Have year on 4 digits from a Date object.........................................................................24 2.3 Get the current Date and Time........................................................................................24 2.4 Compute days between 2 dates......................................................................................25 2.5 Get the number of days in a month ..................................................................................26 2.6 Validate a date.................................................................................................................27 2.6.1 Using DateFormat...................................................................................................27 2.6.2 Using GregorianCalendar.......................................................................................28 2.7 Determine to day of the week..........................................................................................29 2.8 Add/Substract Day/Month/Year to a Date........................................................................29 2.9 Get the correct TimeZone on DateFormat.......................................................................30 2.10 Simply format a date as "YYYYMMDD".........................................................................30 2.11 Compare 2 dates...........................................................................................................31 2.12 Parse a String to obtain a Date/GregorianCalendar object ...........................................31 . 2.13 Use System time to generate unique ID........................................................................32 2.14 Get the day name..........................................................................................................33 2.15 Find the current date format..........................................................................................33 . 2.16 Get a julian date.............................................................................................................34 2.17 Calculate the age...........................................................................................................36 2.18 Format a duration in ms into a string as "Days,Hours,minutes and seconds"...............37 2.19 Get the atomic time........................................................................................................38 2.20 Get a date interval.........................................................................................................40 . 2.21 Determine if an hour is between an interval..................................................................42 . 2.22 Set the computer clock..................................................................................................43

2.23 Use System time to generate unique ID

Real's HowTo@www.rgagnon.com2 Date and Time 2.23 Use System time to generate unique ID........................................................................43 3 AWT ................................................................................................................................................45 3.1 javaawt ..........................................................................................................................45 . 3.2 Use The CardLayout manager........................................................................................45 . 3.3 Detect which card is visible with a CardLayout................................................................47 3.4 Use Popups.....................................................................................................................47 3.5 Use a File Dialog ..............................................................................................................49 3.6 Use TrueType font...........................................................................................................50 3.7 Display available fonts.....................................................................................................51 3.8 Font with 3D effect...........................................................................................................52 3.9 Use the System Clipboard...............................................................................................52 3.10 Maximize a Frame.........................................................................................................53 3.11 Center a Frame/Dialog ...................................................................................................54 3.12 Close a Frame...............................................................................................................55 3.13 Call events on a Frame from a Panel............................................................................56 3.14 Set the small topleft icon on a Frame..........................................................................58 3.15 Prevent a Frame to be resized .......................................................................................59 3.16 Embed an image into a Frame .......................................................................................60 3.17 Display a message box..................................................................................................62 3.18 Display a Splash screen................................................................................................63 3.19 Vibrate a Window...........................................................................................................65 3.20 Limit TextField input to numeric value...........................................................................67 3.21 Limit TextField input to a maximum length....................................................................69 3.22 React to the ENTER key in a Textfield..........................................................................70 3.23 Make the ENTER key act like the TAB key ....................................................................70 3.24 Reset all textfields in one shot.......................................................................................71 3.25 Limit a TextField to Uppercase......................................................................................72 3.26 Have an ImageButton....................................................................................................73 3.27 Reset a checkbox group................................................................................................76 3.28 Set the listbox width.......................................................................................................76 3.29 Align the column in a List...............................................................................................77 3.30 Have a srolling text display............................................................................................77 3.31 Label dynamic resizing..................................................................................................78 3.32 Make a TextArea "wordwrap"......................................................................................80 3.33 Synchronize a TextArea vs a Choice.............................................................................80 3.34 Display underlined text..................................................................................................80 . 3.35 Display vertical text........................................................................................................81 3.36 Have Label with many lines...........................................................................................82 3.37 Have a Label with underlined text..................................................................................86 3.38 Have a Label acting as HTML HREF (URLLabel).........................................................87 3.39 Display a GIF in a Canvas.............................................................................................88 3.40 Embed an image into a Frame .......................................................................................89 3.41 Load several images from a single GIF.........................................................................91 3.42 Load an Image from a JAR file......................................................................................92 3.43 Load an Icon from a jar (again)......................................................................................93 3.44 Scale an Image..............................................................................................................94 3.45 Fade an image...............................................................................................................95 3.46 Rotate an image .............................................................................................................97

Real's HowTo@www.rgagnon.com3 AWT 3.47 Create a scrollable canvas .............................................................................................99 3.48 Use an Image as the Applet background.....................................................................103 3.49 Have a simple Image browser.....................................................................................104 3.50 Simulate a "mouse over" event to toggle an image.....................................................107 3.51 Hide the mouse cursor.................................................................................................108 3.52 Make a color transparent.............................................................................................109 3.53 Save an Image as a GIF or JPEG file..........................................................................110 3.54 Use the same background color as the browser .........................................................111 . 3.55 Do simple animation using Images..............................................................................112 3.56 Do simple animation to show "work in progress".........................................................113 3.57 Get the color of a specific pixel....................................................................................114 3.58 Do "rubberband" drawing ...........................................................................................115 3.59 Convert RGB value to Hexadecimal (to be used in HTML for example) .....................117 . 3.60 Draw a line or set a pixel in my own image ..................................................................117 3.61 Draw a dashed line......................................................................................................118 3.62 Draw a line with a thickness .........................................................................................119 3.63 Draw a pie chart...........................................................................................................121 3.64 Draw faster rectangles.................................................................................................123 3.65 Get a screen capture and save it as a JPEG...............................................................124 3.66 Display a TIF................................................................................................................124 3.67 Convert a multipage TIF into singlepage TIF ...........................................................126 3.68 Convert an Image to a BufferedImage.........................................................................127 3.69 Detect a double click vs simple click............................................................................128 3.70 Detect the mouse button used when clicking ...............................................................129 3.71 Exit an application from a menu ...................................................................................130 3.72 Trigger a click on a Button...........................................................................................131 4 Environment ................................................................................................................................133 4.1 javaenv........................................................................................................................133 4.2 Read environment variables from an application...........................................................133 4.3 Retrieve environment variables (JDK1.5)......................................................................137 4.4 Retrieve environment variable (JNI)..............................................................................137 4.5 Use a MAKE file.............................................................................................................138 4.6 Detect the browser/JVM type.........................................................................................139 4.7 Fix the "Wrong magic number" error message..............................................................141 4.8 Use a precompiler " la C" with Java.............................................................................141 4.9 Open source packages..................................................................................................141 4.10 Ant...............................................................................................................................141 . 4.11 Simple boolean flag.....................................................................................................142 4.12 Determine what are the classes actually used in a Java Applet or application ............143 4.13 Set the memory available to the JVM..........................................................................143 4.14 Generate the Javadoc "en franais"............................................................................143 4.15 Use JDK1.5 new features............................................................................................145 4.16 Check the class version...............................................................................................145 4.17 Get the system properties or the JVM uptime ..............................................................147 4.18 Detect if running in a 64bit JVM...................................................................................147 4.19 Set the default JVM type..............................................................................................148 4.20 Capture the output of JAVAC .......................................................................................149 4.21 Freeze the JVIEW window in MS VJ++.......................................................................150

4.22 Wrap a Java beans in a COM object

Real's HowTo@www.rgagnon.com4 Environment 4.22 Wrap a Java beans in a COM object...........................................................................150 4.23 Know details about the JAVA at runtime...................................................................151 4.24 Detect the Microsoft JVM version installed..................................................................153 4.25 Run JAVA as a Windows service .................................................................................153 4.26 Execute a class from Windows Explorer .....................................................................153 . 4.27 Create an icon to launch java apps for Windows?.......................................................155 4.28 Fix the "out of environment" error when setting a new CLASSPATH..........................155 4.29 Query Windows registry...............................................................................................156 4.30 Quickly retrieve available Java JVM on a workstation (Windows)...............................158 4.31 Get the Windows "My Documents" path......................................................................159 4.32 Get a return code from a VBS ......................................................................................160 4.33 List currently running processes (Windows)................................................................161 4.33.1 Using TASKLIST.EXE .........................................................................................161 4.33.2 Using a VBS ........................................................................................................162 4.34 Check if a program or process is running (Windows)..................................................163 4.35 Windows registry vs. Java JDK/JRE installation..........................................................164 4.36 Create a Taglet to document database access (Javadoc) ..........................................165 . 4.36.1 newMethod .........................................................................................................165 4.37 Generate the Javadoc "en franais"............................................................................169 4.38 Document a package using Javadoc...........................................................................170 4.39 Display a comment in a Javadoc.................................................................................171 4.40 Display XML in a javadoc .............................................................................................172 4.41 Add a copyright notice to a Javadoc............................................................................172 4.42 Use a Log file...............................................................................................................173 4.43 Trace the execution.....................................................................................................175 4.44 Time the execution .......................................................................................................177 4.45 Log information efficiently (with Log4J).......................................................................178 . 4.46 Change the logging level onthefly (Log4J)..............................................................179 4.47 Use a JAR/ZIP/CAB file with an Applet.......................................................................180 . 4.48 Make ZIP/JAR file always accessible from applet.......................................................182 4.49 Make a JAR executable...............................................................................................182 4.50 Accessing jars from within a jar...................................................................................184 4.51 Access a JAR outside the CLASSPATH ......................................................................184 4.52 Extract a file from a Jar................................................................................................185 4.53 Determine if running from JAR .....................................................................................186 4.54 Get list of classes in package (in a Jar).......................................................................187 4.55 Add version to Jar packaging .......................................................................................188 4.56 Use ANT to Build a JAR with version/build number.....................................................190 4.57 Include all jars in the classpath definition .....................................................................193 4.58 Windows batch file.......................................................................................................194 4.59 JDK6............................................................................................................................194 4.60 JAR (and ANT)............................................................................................................195 . 4.61 Detect the browser/JVM type.......................................................................................196 4.62 Detect if Java is enabled from HTML...........................................................................198 4.63 See the Java Console Window Log (Java plugin).......................................................198 5 Internationalization .....................................................................................................................200 5.1 javainter.......................................................................................................................200 5.2 Load resources based upon client environment at startup............................................200

Real's HowTo@www.rgagnon.com5 Internationalization 5.3 Load resources dynamically..........................................................................................203 5.4 Load resources via a resources file...............................................................................206 5.5 Display "special character" using Unicode .....................................................................210 5.6 Display chinese/japanese characters............................................................................211 5.7 Localize a JOptionPane dialog......................................................................................211 5.8 Validate/Convert a number using the current Locale()..................................................213 5.9 Localize a JFileChooser................................................................................................214 . 5.10 Disable localization......................................................................................................216 5.11 Generate the Javadoc "en franais"............................................................................217 5.12 Sort a String array........................................................................................................218 5.13 Accentuated characters in Properties/ResourceBundle file.........................................220 5.14 Compare accentuated letters.......................................................................................220 5.15 Unaccent letters...........................................................................................................221 5.16 Output french characters to the console......................................................................224 5.17 Get the default character set of the JVM.....................................................................225 5.18 Convert OEM (DOS) file to Ansi (Windows)................................................................225 5.19 Detect nonASCII character in a String.......................................................................226 6 IO..................................................................................................................................................228 6.1 javaio...........................................................................................................................228 6.2 Redirect output(stdout/stderr) to a frame.......................................................................228 6.3 Redirect printStackTrace() to a String ............................................................................229 6.4 Output french characters to the console........................................................................230 6.5 Clear the console and control attributes........................................................................231 6.6 Print text to a printer easily............................................................................................232 6.7 Print without a Dialog.....................................................................................................232 6.8 Simple input from the keyboard.....................................................................................233 6.9 Initialize and write to a serial port..................................................................................234 . 6.10 Redirect to a NULL device...........................................................................................235 6.11 Get the volume label....................................................................................................235 6.12 Easy keyboard input (JDK1.5).....................................................................................236 6.13 Open or close a CD/DVD drive....................................................................................236 6.14 Get faster console output (System.out.println() replacement).....................................238 6.15 Execute an external program.......................................................................................239 6.16 Using Runtime.exec()..................................................................................................239 6.17 Launch a Windows CMD (or BAT) file and retrieve the errorlevel or exitcode .............240 6.18 Launch a Unix script....................................................................................................241 6.19 Using the ProcessBuilder............................................................................................241 . 6.20 Windows rundll32 utility...............................................................................................242 6.21 PDF (Windows only)....................................................................................................242 6.22 PDF (Mac only)............................................................................................................242 6.23 Path to executable with spaces in them .......................................................................243 6.24 VBSCRIPT...................................................................................................................243 6.25 HTML Help (Windows only).........................................................................................243 6.26 Start Excel...................................................................................................................243 . 6.27 Start a Windows application under another account...................................................244 . 6.28 Windows : execute something in Program Files..........................................................245 6.29 Launch the application associated with a file extension..............................................245 6.30 Launch an application from another application..........................................................246

6.31 Start the default browser from an application

Real's HowTo@www.rgagnon.com6 IO 6.31 Start the default browser from an application..............................................................248 6.32 Execute a Windows Shortcut (.lnk)..............................................................................250 6.33 Create a file association with a Java program.............................................................250 6.34 Capture the output from a VBS....................................................................................252 6.35 Get a return code from a VBS ......................................................................................253 6.36 Execute a CMD file stored in a JAR .............................................................................254 6.37 Read the content of a file.............................................................................................255 6.38 Read a text file from a jar.............................................................................................257 6.39 Extract a file from a Jar................................................................................................260 6.40 Read a data file with floats...........................................................................................261 6.41 Write to the end of a file...............................................................................................262 6.42 Write "real" ascii file.....................................................................................................263 6.43 Copy a file....................................................................................................................264 6.44 Use a "log file" ..............................................................................................................266 6.45 Delete files with a certain extension .............................................................................267 6.46 Insert a line in a file......................................................................................................268 6.47 Read a file into a variable in one shot..........................................................................269 6.48 Serialize an object to a file...........................................................................................269 6.49 Redirect stdout to a file................................................................................................271 6.50 Get the "last modified" date from a file .........................................................................271 6.51 Check if a file exists.....................................................................................................271 6.52 Detect file modification.................................................................................................272 6.53 File/directory polling to detect change.........................................................................274 6.54 jpoller (directory poller)................................................................................................274 6.55 JNotify..........................................................................................................................274 6.56 Java Native Access (JNA)...........................................................................................275 6.57 Call native methods in a DLL from Java (NativeCall)..................................................275 6.58 Java 7..........................................................................................................................275 6.59 The simple (and naive!) approach...............................................................................275 6.60 Get the current directory..............................................................................................275 6.61 Get the "root" of an application....................................................................................276 6.62 Get the content of a directory with a Filter...................................................................276 6.63 Get the content of a directory with subdirectories........................................................278 6.64 Make a directory..........................................................................................................279 6.65 Create a fixedlength file.............................................................................................280 6.66 Delete a nonempty directory......................................................................................280 6.67 Create a temporary file................................................................................................281 6.68 Get the default character set of the JVM.....................................................................282 6.69 Parse a pathname ........................................................................................................282 6.70 Handle Excel files........................................................................................................283 6.71 JDBCODBC Excel driver...........................................................................................283 6.72 JExcel..........................................................................................................................283 6.73 POI...............................................................................................................................284 6.74 JXLS............................................................................................................................285 6.75 xlSQL...........................................................................................................................285 6.76 JCOM...........................................................................................................................286 6.77 OpenXLS Java Spreadsheet SDK...............................................................................287 6.78 Handle CSV file ............................................................................................................289 6.79 com.Ostermiller.util CSV Utils......................................................................................289

Real's HowTo@www.rgagnon.com6 IO 6.80 opencsv ........................................................................................................................289 6.81 ServingXML.................................................................................................................289 6.82 Super CSV...................................................................................................................289 6.83 csvreader.....................................................................................................................289 6.84 CSVFile........................................................................................................................289 6.85 FlatPack.......................................................................................................................289 6.86 Create an Excel file......................................................................................................290 6.87 Create or process a PDF file ........................................................................................290 6.88 Create a PDF...............................................................................................................292 6.89 iText.............................................................................................................................292 6.90 Convert OEM (DOS) file to Ansi (Windows)................................................................293 6.91 Close a stream in a try/catch block..............................................................................294 6.92 Rename a file extension..............................................................................................295 6.93 Remove HTML tags from a file to extract only the TEXT .............................................295 6.94 Using regular expression.............................................................................................296 6.95 Using javax.swing.text.html.HTMLEditorKit.................................................................296 6.96 Get the Mime Type from a File....................................................................................297 6.96.1 Using javax.activation.MimetypesFileTypeMap..................................................297 6.96.2 Using java.net.URL.............................................................................................298 6.96.3 Using JMimeMagic ..............................................................................................298 6.96.4 Using mimeutil..................................................................................................298 6.96.5 Using Droid.........................................................................................................299 6.96.6 Aperture framework .............................................................................................299 6.97 Sort a directory listing..................................................................................................299 6.98 Filter a directory listing by date....................................................................................300 6.99 Display a comment in a Javadoc.................................................................................301 6.100 Create a compressed (ZIP) file..................................................................................302 6.101 Display compressed (ZIP) file content.......................................................................303 6.102 Expand the compressed (ZIP) file ..............................................................................304 6.103 Emit a beep................................................................................................................305 6.104 Emit a Tone ................................................................................................................305 6.105 Play an audio file from an application........................................................................306 7 JDBC............................................................................................................................................308 7.1 javajdbc ........................................................................................................................308 7.2 Connect to a database via JDBCODBC......................................................................308 7.3 SELECT data from a table.............................................................................................309 7.4 INSERT data into a table...............................................................................................310 7.5 MODIFY data in a table.................................................................................................311 7.6 DELETE data in a table.................................................................................................312 7.7 Test for an empty ResultSet..........................................................................................312 7.8 Store and retrieve an object from a table.......................................................................313 7.9 Retrieve an Image ..........................................................................................................315 7.10 Insert an Image............................................................................................................315 7.11 Connect to an Oracle database with JDBC.................................................................315 7.12 Connect to Oracle using a connection pool.................................................................316 7.13 Get JDBC driver for major database vendors..............................................................319 7.14 Handle dates................................................................................................................319 7.15 Call a stored procedure ................................................................................................320

7.16 Stored procedure with Input/Output parms and a ResultSet

Real's HowTo@www.rgagnon.com7 JDBC 7.16 Stored procedure with Input/Output parms and a ResultSet.......................................321 7.17 Fix incomplete field returned by the ResultSet............................................................322 7.18 Get a record count with a SQL Statement...................................................................322 7.19 Transfer a ResultSet to a JTable.................................................................................323 7.20 List tables in a database..............................................................................................323 7.21 Display ResultSet data in an HTML Table in Servlet...................................................324 7.22 Detect SQL errors or warnings....................................................................................325 7.23 Using DSNless connection........................................................................................326 7.24 Read data from Excel worksheet.................................................................................327 7.25 Handle Excel files........................................................................................................329 7.26 JDBCODBC Excel driver...........................................................................................329 7.27 JExcel..........................................................................................................................329 7.28 POI...............................................................................................................................330 7.29 JXLS............................................................................................................................330 7.30 xlSQL...........................................................................................................................331 7.31 JCOM...........................................................................................................................331 7.32 OpenXLS Java Spreadsheet SDK...............................................................................333 7.33 Specify a CharSet when connecting to a DBMS ..........................................................334 7.34 Get current date using JDBC.......................................................................................335 7.35 Enable JDBC logging...................................................................................................335 7.36 Detect if a table exists..................................................................................................337 7.37 Convert a ResultSet to XML........................................................................................337 7.38 Escape special character in a LIKE clause..................................................................339 7.39 Insert the current date..................................................................................................340 7.40 Log the SQL Statements ..............................................................................................340 7.41 Plain JDBC Logging.....................................................................................................340 7.42 P6Spy..........................................................................................................................340 7.43 Proxool.........................................................................................................................341 8 JNI................................................................................................................................................342 8.1 javajni ..........................................................................................................................342 . 8.2 Use native code through JNI.........................................................................................342 . 8.3 Pass a string to/from Java to/from C ..............................................................................342 8.4 Set the computer clock..................................................................................................344 8.5 Determine the signature of a method .............................................................................344 8.6 Use arrays ......................................................................................................................346 8.7 Load a DLL....................................................................................................................347 8.8 Use the MouseWheel....................................................................................................347 . 8.9 Throw an Exception (from JNI code).............................................................................347 8.10 Throw my own Exception (from JNI code)...................................................................348 8.11 JNI from a package......................................................................................................349 8.12 Make a Window "stay on top"......................................................................................349 8.13 Start a JVM from C......................................................................................................350 8.14 Retrieve environment variable (JNI)............................................................................351 8.15 Get the PID..................................................................................................................351 8.16 Clear the console, set color and cursor position (JNI).................................................352 8.17 Call Windows API (Open source solution)...................................................................355

Real's HowTo@www.rgagnon.com9 Javascript interaction .................................................................................................................356 9.1 javajs ............................................................................................................................356 9.2 * Read me * ....................................................................................................................356 9.3 Wakeup a Java applet.................................................................................................356 9.4 Call a Java method from Javascript...............................................................................358 9.5 Calling Java applets methods using DOM and JavaScript............................................360 9.6 Access Java variables from Javascript..........................................................................360 9.7 Call Javascript from a Java applet.................................................................................361 9.8 Create dynamic HTML from a Java applet....................................................................364 9.9 Have Applets on different frames communicates with each other.................................365 9.10 Send a message from an Applet to another Applet on a different page......................366 9.11 Retrieve values from a Java applet for HTML form (CGI) ...........................................368 . 9.12 Detect if an Applet is ready..........................................................................................369 9.13 Read/Write HTML field values from JAVA...................................................................370 9.14 Detect if Java is enabled..............................................................................................372 9.15 Detect if Java 1.1 (with event delegation) is available.................................................372 9.16 Access Cookies from a Java Applet............................................................................372 9.17 Set Applet PARAM VALUE from javascript.................................................................375 9.18 Pass an Array between Java and Javascript...............................................................376 9.19 Interaction without LiveConnect...................................................................................378 9.20 Directory listing on the Web server in a Java Applet...................................................382 9.21 Have a Java button close the browser window............................................................384 9.22 Detect if cookies are enabled .......................................................................................385 9.23 Display a page after all applets are loaded..................................................................386 10 Servlet/JSP................................................................................................................................387 10.1 javajsp ........................................................................................................................387 10.2 Read me......................................................................................................................387 10.3 Get parameters passed to a servlet.............................................................................387 10.4 Detect no argument condition in a Servlet...................................................................388 10.5 Set a Cookie from a servlet.........................................................................................389 . 10.6 Read a Cookie from a servlet......................................................................................389 10.7 Delete (or expire) a Cookie from a servlet...................................................................390 10.8 Ask for a password from a Servlet...............................................................................390 10.9 Talk to a CGI/Servlet...................................................................................................390 . 10.10 Test for Cookies.........................................................................................................391 10.11 Display ResultSet data in an HTML Table in Servlet.................................................392 10.12 Specify the filename to be used for a file sent by a Servlet.......................................393 10.13 Pass information to another servlet/jsp......................................................................393 10.14 Handle PDF output....................................................................................................394 10.15 Detect if the connection is via a secure channel........................................................394 10.16 In a Servlet, check if Form Field is present................................................................394 10.17 Get the root dir of a web app.....................................................................................395 10.18 Get client IP address from JSP..................................................................................395 10.19 Output a binary stream from a JSP ............................................................................395 10.20 Use a connection cache from JSP.............................................................................396 10.21 Read a Web Application property..............................................................................397 10.22 Use EJB from JSP.....................................................................................................398 10.23 Define a method in a JSP page.................................................................................398 10.24 Precompile JSP pages ...............................................................................................399

10.25 Get a list of directories for JSP

Real's HowTo@www.rgagnon.com10 Servlet/JSP 10.25 Get a list of directories for JSP..................................................................................400 10.26 Use and share a class in JSP pages.........................................................................400 10.27 Get the root dir of a web app.....................................................................................402 10.28 Launch an applet from a JSP .....................................................................................402 10.29 Prevent caching of a JSP output...............................................................................403 . 10.30 Call another EJB........................................................................................................403 10.31 Keep java files generated from JSP (BEA WLS).......................................................404 10.32 Get the server version (BEA WLS)............................................................................404 10.33 Quickly create a Web application with BEA WLS......................................................405 10.34 Nicely display WEB.XML informations.......................................................................405 10.35 Reverse the CLASSLOADER order (BEA)................................................................406 10.36 Detect change in JSP and recompile (BEA)..............................................................407 11 Language ...................................................................................................................................408 11.1 javalanguage.............................................................................................................408 11.2 * Read me * ..................................................................................................................408 11.3 Obtain from where a Class is loaded...........................................................................409 11.4 Get the class name in a static method.........................................................................410 11.5 Get the current method name......................................................................................410 11.6 Call a method dynamically (Reflection) .......................................................................411 . 11.7 Detect if a package is available...................................................................................413 11.8 Create an object from a string ......................................................................................414 11.9 Get a variable value from the variable name...............................................................415 11.10 Make methods that have unspecified number of parameters....................................416 11.11 Create a java source dynamically, compile and call..................................................417 11.12 Launch an application from another application........................................................418 11.13 Access the enclosing class from an inner class .........................................................419 11.14 Access inner class from outside................................................................................420 11.15 Use globally defined constants..................................................................................421 11.16 Serialize an Object.....................................................................................................422 11.17 Serialize an Object over a socket..............................................................................424 11.18 Easily remove my debugging code............................................................................424 11.19 Have a singleton........................................................................................................425 11.20 Multiple expressions in for loops................................................................................426 11.21 Handle the List conflict...............................................................................................426 11.22 Use a generic toString().............................................................................................426 11.23 Use Object.clone().....................................................................................................428 11.24 Static field, constructor and exception.......................................................................429 11.25 Use a Label break......................................................................................................430 11.26 Put printStackTrace() into a String.............................................................................431 11.27 Use a Hashtable........................................................................................................431 11.28 Scan the content of a hashtable................................................................................432 11.29 Sort an array..............................................................................................................432 11.30 Initialize multidimensional array.................................................................................434 11.31 Get array upperbound................................................................................................434 11.32 Convert a String to an array.......................................................................................435 11.33 Sort in reverse order..................................................................................................436 11.34 Resize an array..........................................................................................................436 11.35 Dump array content...................................................................................................437

Real's HowTo@www.rgagnon.com11 Language 11.36 Initialize a static array................................................................................................438 11.37 Sort an Hashtable......................................................................................................439 11.38 Eliminate "[unchecked] unchecked call ..." compiler warning....................................440 12 ANT............................................................................................................................................442 12.1 Sort on many fields......................................................................................................442 12.2 Optimize Collection usage...........................................................................................444 12.3 Sort an HashMap.........................................................................................................446 12.4 Get a key from value with an HashMap.......................................................................446 12.5 Iterate a Collection and remove an item......................................................................447 12.6 Count distinct elements in a Vector.............................................................................448 12.7 Dump the content of a Collection (JDK 1.5)................................................................450 . 12.8 Use an INI file (properties)...........................................................................................450 12.9 Load a properties file...................................................................................................452 12.10 Accentuated characters in Properties/ResourceBundle file.......................................452 12.11 Have a multiline value in a properties file................................................................453 12.12 Use XML with Properties...........................................................................................453 12.13 Use the Registry to store informations (Preferences API).........................................454 12.14 Sort Properties when saving......................................................................................455 13 Networking................................................................................................................................457 13.1 javanet.......................................................................................................................457 13.2 Extract network card address......................................................................................457 13.3 Get the workstation name/ip........................................................................................459 13.4 Find port number not in use.........................................................................................461 13.5 Disable DNS caching...................................................................................................461 13.6 Encode/Decode to/from Base64..................................................................................462 13.7 Using javax.mail.internet.MimeUtility...........................................................................463 13.8 Using Apache Commons Codec..................................................................................463 13.9 MiGBase64..................................................................................................................464 13.10 Lookup using MX record to validate mail server........................................................464 13.11 Send an email using the SMTP protocol...................................................................472 . 13.12 Check if there is mail waiting.....................................................................................474 13.13 Receive email............................................................................................................475 13.14 Send email with an attachment..................................................................................477 13.15 Send email with JavaMail..........................................................................................483 13.16 Send email with authentication..................................................................................485 13.17 Send HTML mail with images (Javamail) ..................................................................486 . 13.18 Debug a Javamail Program.......................................................................................488 13.19 Send email with SMTPS (eg. Google GMail) (Javamail)...........................................489 13.19.1 Settings for well known mail providers..............................................................490 13.20 Mix plain text and HTML content in a mail.................................................................490 13.21 Read an Outlook MSG file.........................................................................................491 13.22 msgparser..................................................................................................................491 13.23 Apache POI HSMF....................................................................................................492 13.24 jmbox.........................................................................................................................492 13.25 Handle EML file with JavaMail...................................................................................492 13.26 Check if a file was modified on the server.................................................................493 13.27 Check if a page exists................................................................................................494

13.28 Connect through a Proxy

Real's HowTo@www.rgagnon.com13 Networking 13.28 Connect through a Proxy...........................................................................................495 13.29 Identify yourself using HTTP Authentification............................................................498 13.30 Talk to a CGI/Servlet.................................................................................................500 . 13.31 Write/Read cookies using HTTP................................................................................501 13.32 Read a GIF or CLASS from an URL save it locally ....................................................503 13.33 Resolve a relative URL..............................................................................................504 13.34 File size from URL.....................................................................................................505 13.35 Use the HTTPS protocol............................................................................................505 13.36 Fetch a page from Google.........................................................................................506 13.37 Upload a file to a server.............................................................................................507 13.38 Connect through a Proxy...........................................................................................507 13.39 Have timeout on socket connection...........................................................................510 13.40 Ping a server..............................................................................................................510 13.41 Get the Date from server...........................................................................................511 13.42 Get the client IP address ............................................................................................512 13.43 Use the java.net.Socket.setSoLinger method............................................................512 13.44 Use the java.net.Socket.setTcpNoDelay method......................................................513 13.45 Find out who is accessing my ServerSocket.............................................................513 13.46 Transfer a file via Socket...........................................................................................513 14 Security ......................................................................................................................................516 14.1 javasecurity................................................................................................................516 14.2 Encrypt a password.....................................................................................................516 14.3 Create a checksum......................................................................................................518 14.4 Get the user name.......................................................................................................521 14.5 Get username using NT Challenge (NTLM)................................................................521 14.6 Check if the current user belongs a specific Windows group/role...............................523 14.7 Prompt for password from the console........................................................................523 14.8 Prevent XSS exploit.....................................................................................................524 14.9 Sanitize the input by removing suspicious tags...........................................................525 14.10 Sanitize the output by removing suspicious characters.............................................525 14.11 Display a simple username/password Dialog from an Applet....................................526 15 Swing.........................................................................................................................................529 15.1 javaswing...................................................................................................................529 15.2 * Read me * ..................................................................................................................529 15.3 Change component default font...................................................................................529 15.4 Repaint problem under the mouse cursor (JDK1.2)....................................................530 15.5 Set the LookAndFeel...................................................................................................530 15.6 Use any LookAndFeel on any plateform......................................................................530 15.7 Use a Timer.................................................................................................................531 15.8 Share ActionEvent handler..........................................................................................531 15.9 Get default values for Swingbased user interface.....................................................533 15.10 Have a systray icon (Windows) .................................................................................534 . 15.11 Close a JFrame under condition................................................................................536 15.12 Maximize a JFrame ....................................................................................................537 15.13 Capture System.out into a JFrame............................................................................538 15.14 Remove the titlebar of JInternalFrame .......................................................................540 15.15 Have borders on a JWindow/JFrame .........................................................................540

Real's HowTo@www.rgagnon.com15 Swing 15.16 Display HTML in a JScrollPane.................................................................................541 15.17 Use a JOptionPane....................................................................................................542 15.18 Localize a JOptionPane dialog..................................................................................543 15.19 Customize JOptionPane buttons...............................................................................545 15.20 Localize a JFileChooser............................................................................................545 . 15.21 Select a directory with a JFileChooser ......................................................................548 . 15.22 Disable the JFileChooser's "New folder" button .........................................................549 15.23 Validate a filename from a JFileChooser...................................................................550 15.24 Make a JFrame looks like a JDialog..........................................................................552 15.25 Based on JTextField content, enable or disable a JButton........................................553 15.26 Apply special filter to a JtextField ...............................................................................553 15.27 Limit JTextField input to a maximum length ...............................................................556 15.28 Validate a value on the lostFocus event....................................................................557 15.29 Make sure that my jTextfield has the focus when a JFrame is created.....................559 15.30 Stop the beep on JFormattedTextField ......................................................................560 15.31 Right justified JTextfield content................................................................................560 15.32 Set the focus on a particuliar JTextField....................................................................561 15.33 Make JTextField unselectable...................................................................................561 15.34 Use a JTree to navigate in a site...............................................................................562 15.35 Expand or collapse a JTree.......................................................................................568 15.36 Have a popup attached to a JTree .............................................................................570 15.37 Traverse a JTree ........................................................................................................572 15.38 Show dotted lines in a JTree ......................................................................................574 15.39 Explore directories with a JTree .................................................................................574 15.40 Prevent JTree collapsing...........................................................................................575 15.41 Single selection in a JTree.........................................................................................576 15.42 Reduce JTree children indentation............................................................................576 15.43 Use + or for JTree Icons.........................................................................................576 15.44 Change the JTable header color...............................................................................578 . 15.45 Double click on a JTable............................................................................................578 15.46 Read a data file into a JTable....................................................................................580 15.47 Disable row selection in a JTable..............................................................................583 15.48 Read a data file into a JTable and reload if data file have changed..........................583 15.49 Hide a column in JTable............................................................................................585 15.50 Scroll a JTable to the last row....................................................................................586 15.51 Transfer a ResultSet to a JTable...............................................................................587 15.52 Have on a JScrollPane/JTable an horizontal JScrollbar............................................587 15.53 Make a JList select an item on doubleclick or the ENTER key..................................588 15.54 Make a JList like a scrolling text display....................................................................589 15.55 Have images in a JList...............................................................................................590 15.56 Add a row and clear a JList.......................................................................................592 . 15.57 Sort a JList.................................................................................................................593 15.58 Double click on a JList...............................................................................................595 15.59 Have a PopUp on a JList...........................................................................................596 15.60 Make a JLabel selectable with the mouse.................................................................597 15.61 Change JLabel background color..............................................................................598 15.62 Bold / Unbold a JLabel...............................................................................................598 15.63 Multiline JLabel........................................................................................................598 15.64 Underline a string.......................................................................................................598

15.65 Update a JLabel

Real's HowTo@www.rgagnon.com15 Swing 15.65 Update a JLabel.........................................................................................................599 15.66 Display a blinking JLabel...........................................................................................599 15.67 Set the cursor position in a JTextArea.......................................................................601 15.68 Have Multiline string in a JToolTip...........................................................................601 15.69 Change Tooltip color..................................................................................................602 15.70 Change a JTooltip font...............................................................................................602 15.71 Keep a JTooltip visible...............................................................................................603 15.72 Display icon associated with an executable ...............................................................603 15.73 Have items in JMenubar at rightmost position...........................................................605 15.74 Have an JButton with an Image.................................................................................606 15.75 Trigger a click on a Button.........................................................................................607 16 Thread ........................................................................................................................................609 16.1 javathread..................................................................................................................609 16.2 Pipe the output of a thread to the input of another one ................................................609 16.3 Pipe the output of a thread to the input of other threads ..............................................611 16.4 Wait the for the completion of a thread........................................................................613 16.5 Control a thread from outside......................................................................................614 16.6 Create a Timer object..................................................................................................615 16.7 Pause the execution....................................................................................................616 16.8 Execute a method at a specified time interval.............................................................616 16.9 Execute a process at regular interval..........................................................................618 . 16.10 Handle concurrent read/write.....................................................................................619 16.11 Communicate between threads using a Queue.........................................................620 16.12 Get a unique identifier................................................................................................625 16.13 Using java.rmi.dgc.VMID...........................................................................................625 16.14 Using java.util.UUID...................................................................................................625 16.15 Using Apache commons............................................................................................626 16.16 Using java.util.concurrent.AtomicLong .......................................................................626 17 Varia...........................................................................................................................................627 17.1 javavaria....................................................................................................................627 17.2 Use System time to generate unique ID......................................................................627 17.3 Get a unique identifier..................................................................................................627 17.4 Using java.rmi.dgc.VMID.............................................................................................627 17.5 Using java.util.UUID.....................................................................................................628 17.6 Using Apache commons..............................................................................................628 17.7 Using java.util.concurrent.AtomicLong .........................................................................628 17.8 Get the hard disk serial number or Motherboard serial number..................................629 17.9 Motherboard serial number..........................................................................................629 17.10 Hard disk serial number.............................................................................................630 17.11 Sort an array..............................................................................................................631 17.12 Sort a String array......................................................................................................632 17.13 Do a selection sort.....................................................................................................634 17.14 Validate a Social Security Number (canadian)..........................................................635 17.15 Validate a Credit Card Number..................................................................................636 17.16 Obtain from where a Class is loaded.........................................................................639 17.17 Get the class name with or without the package.......................................................640 17.18 See the generated bytecode......................................................................................641

Real's HowTo@www.rgagnon.com17 Varia 17.19 Self replicating programs...........................................................................................644 17.20 A curiosity (strange Java code).................................................................................645 . 17.21 Classic bugs ...............................................................................................................646 17.22 Number of the beast!.................................................................................................647 17.23 Preventing multiple instances of an application.........................................................648 17.24 Trap JVM shutdown...................................................................................................651 17.25 Use Java scripting engine (JDK 1.6).........................................................................651 . 18 XML............................................................................................................................................653 18.1 javaxml ......................................................................................................................653 . 18.2 Read me......................................................................................................................653 18.3 Display XML using plain HTML....................................................................................654 18.4 Transform XML into HTML using XSLT.......................................................................655 18.5 Parse using SAX or DOM............................................................................................656 18.6 Parse an XML string....................................................................................................658 18.7 Create an XML document with DOM...........................................................................659 18.8 Attach a stylesheet to an XML file ................................................................................661 18.9 Create an XML file and attach an XSL .........................................................................662 18.10 Nicely display WEB.XML informations.......................................................................665 18.11 Serialize an object using XML ....................................................................................666 18.12 Convert a flat file to XML (SAX).................................................................................667 18.13 Convert a flat file to XML (DOM)................................................................................669 18.14 Convert a ResultSet to XML......................................................................................672 18.15 Parse with XPath.......................................................................................................674 18.16 Strip extra spaces in a XML string.............................................................................675 18.17 Create an XML file and attach an XSL .......................................................................676 18.18 Use XML with Properties...........................................................................................679 18.19 Change a particular node in XML..............................................................................680 18.20 Create a RSS feed (part 1)........................................................................................681 18.20.1 RSS 2.0 .............................................................................................................681 18.20.2 Atom ..................................................................................................................682 18.20.3 Creating a feed ..................................................................................................683 18.20.4 Creating a feed with Apache Commons Digester.............................................683 18.20.5 Creating a feed with Rome ................................................................................685 18.21 Creating an RSS Feed (part 2)..................................................................................686 18.22 Parse a RSS XML file................................................................................................692 18.22.1 Parsing a feed with Apache Commons Digester..............................................692 . 18.22.2 P