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Java: AP Curriculum Focusand Java Subset

Java: AP Curriculum Focusand Java Subset

Alyce Brady

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Curriculum TopicsCurriculum Topics

Object-oriented programming and designDeclaring and constructing objectsInvoking methodsInteracting objectsClass implementations, including method

implementations• Parameter passing

• Basic control flow constructs

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Curriculum Topics (continued)Curriculum Topics (continued)

Data StructuresPrimitive typesClassesArrays and ArrayLists Maps and Sets (AB)Stacks and Queues (AB)Linked Lists (AB)Trees (AB)Heaps, Priority Queues (AB)

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Curriculum Topics (continued)Curriculum Topics (continued)

AlgorithmsTraversing Linear Data Structures

• Accumulate

• Find Min/Max

Searching (e.g., linear, binary)SortingTraversing Linked Lists and Trees (AB)Analyzing space and time performance (formal

analysis -- AB)

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AP Java SubsetAP Java Subset

Why have a subset?Language is big; can’t cover everything.Libraries are bigger; can’t cover everything.Exam can’t test everything.Exam should test fundamental ideas, not every

esoteric (or interesting, or even useful) language construct.

Subset defines/limits what may be on the exam, not what you can cover.

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Java SubsetJava Subset

Primitive Types (similar to C++)int, double, booleanarithmetic operators: + - * / % ++ --relational & logical: == != < <= && || !assignment: = += etc.numeric casting: (int) (double), truncation

char is not required by subset

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Java Subset (continued)Java Subset (continued)

String class (similar to apstring)Declaring and constructing stringsString constants String concatenation (+)

• converting numerics to strings

• converting objects to strings (toString)

Escape sequences: \\ \” \n

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Java Subset (continued)Java Subset (continued)

I/O System.out.print, System.out.println No other I/O will be tested, so you can use

whatever techniques you and your textbook choose, e.g., keyboard input, text fields in graphical user interfaces, mouse events, applets, etc.

Case study also uses Debug.print, Debug.println

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Java Subset (continued)Java Subset (continued)

Control Structures (similar to C++) if, if - else, if - else if -

else for, while return

Comments (similar to C++) // /* … */ Case study uses doc. comments /** … */

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Java Subset (continued)Java Subset (continued)

Using Objects Constructing objects using new, passing

parameters to constructors as necessary Variables are references to objects Dot notation for invoking methods Use of this to pass self to other objects Difference between == and equals

null reference

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Java Subset (continued)Java Subset (continued)

Defining Classes public/private static final

constants private instance variables (data members) public and private constructors and

methods (member functions)

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Java Subset (continued)Java Subset (continued)

Methods Method calls and method definitions Constructors, accessors, modifiers Parameter passing (always pass-by-value, but

passing references by value feels like pass-by-reference)

Method overloading; signature depends on number, type, order of parameters

super.method to call overridden method definition

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Java Subset (continued)Java Subset (continued)

Constructors (similar to C++) Name is same as class; no return value Initialize instance variables in constructors (no

initialization lists) Call super to initialize inherited data

static constants are initialized when declared:public static final CONSTANT =

init_expr;

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Java Subset (continued)Java Subset (continued)

Standard Java Library Classes (A list)java.lang.Objectjava.lang.Comparable (AB only?)java.lang.Integer, java.lang.Doublejava.lang.Stringjava.util.ArrayListjava.lang.Mathjava.util.Random

import statement

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Java Subset (continued)Java Subset (continued)

Linear Indexed Data Structures1D (A) and 2D (AB) arrays, similar to apvector

• bounds checking

• myArray[i].length

• 2D arrays are AB material

ArrayList class• Core subset of methods

• Casting from Object to specific class (and casting more generally in other contexts)

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Java Subset (continued)Java Subset (continued)

Inheritance and InterfacesImplementing interfacesExtending classes

• inheriting data and methods

• overriding methods

• dynamic binding (polymorphism)

Abstract classes

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Java Subset (continued)Java Subset (continued)

Exceptions (unchecked exceptions)Understand when they occurNullPointerException, ArrayIndexOutOfBoundsException, ArithmeticException, ClassCaseException, IllegalStateException, NoSuchElementException

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Java Subset (continued)Java Subset (continued)

What is NOT in the subset (not testable)?char

most I/Omain method (used in case study) and appletsdo/while, switch, breakprotected visibility (used in case study)many other features

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Java Subset (AB Additions)Java Subset (AB Additions)

Standard Java Library Classesjava.lang.Comparable (officially AB only)java.util.List (interface)java.util.ArrayList implements java.util.Listjava.util.LinkedList implements java.util.Listjava.util.Set (interface)java.util.HashSet implements java.util.Setjava.util.TreeSet implements java.util.Setjava.util.Iteratorjava.util.ListIterator extends java.util.Iterator

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Standard Java Lists (java.util)Standard Java Lists (java.util)

List (interface)boolean add(Object x)int size()Iterator iterator()ListIterator listIterator()

ArrayListObject get(int index)Object set(int index, Object x)void add(int index, Object x)Object remove(int index)

LinkedListvoid addFirst(Object x)void addLast(Object x)Object getFirst()Object getLast()Object removeFirst()Object removeLast()

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Standard Java Sets (java.util)Standard Java Sets (java.util)

Set (interface)boolean add(Object x)boolean contains(Object x)boolean remove(Object x)int size()Iterator iterator()

HashSet TreeSet

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Standard Java Lists (java.util)Standard Java Lists (java.util)

Iterator (interface)boolean hasNext()Object next()void remove()

ListIterator (interface)void add(Object x)void set(Object x)

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Collections (NOT in Subset!)Collections (NOT in Subset!)

Collection (interface)boolean add(Object x)boolean contains(Object x)boolean remove(Object x)int size()Iterator iterator()

ListListIterator listIterator()

Set

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Java Subset (AB Additions)Java Subset (AB Additions)

Standard Java Library Classesjava.util.Map (interface)java.util.HashMapJava.util.TreeMapjava.lang.Object

• int hashCode()

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Standard Java Maps (java.util)Standard Java Maps (java.util)

Map (interface)Object put(Object key, Object value))Object get(Object key)boolean containsKey(Object key)int size()Set keySet()

HashMap TreeMap

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Java Subset (AB Additions)Java Subset (AB Additions)

AP CS ListNode and TreeNode Classes

Interfaces for Stack, Queue, PriorityQueueThere is a java.util.Stack class, but this is not the

same as the AP interface and is not in the subset