Java Debugging in Eclipse

by

Dr. Bun YueProfessor of Computer Science

yue@uhcl.eduhttp://sce.uhcl.edu/yue/

2013

CSCI 3333 Data Structures

General Resources

Like other IDE, Eclipse includes a good debugger for Java.

Allows developers to control program execution for investigation.

http://help.eclipse.org/juno/index.jsp: check the section on debugging.

Java Editor

The editor already provides assistance in program development and debugging.

Example

Perspective

Debugging

Likes solving mystery and puzzles, CSI, etc.

You need to have:1. Domain knowledge2. Reasoning3. Investigating and looking for clues4. Making and testing hypothesis

A debugger can help in (3) and (4).

Java Debugging

To debug a Java program, use one of the following: the debug button Run > Debug As > Java Application After confirmation, a debug perspective

(view) is open. You can check variable values during program suspension by breakpoints.

Breakpoints

Can be used to suspend program execution.

Developers can then check variable values.

Can be disabled.

Example

Example

Variable view

Actions after halted

Examples: Step into, Skip all breakpoints, Step Return, drop to frame, etc.

Method breakpoint

Watchpoint

A watchpoint is used to watch a variable.

The debugger halts when the variable is accessed.

You can toggle a watchpoint on a variable by right-clicking the declaration line of the variable.

Hit Count

More tips

More features and tips from http://javapapers.com/core-java/top-10-java-debugging-tips-with-eclipse/. E.g. Watch points Conditional breakpoints …

Video tutorial: http://eclipsetutorial.sourceforge.net/debugger.html

More tutorial

http://www.vogella.com/articles/EclipseDebugging/article.html

Questions and Comments?