The AP Java Subset

1
The AP Java Subset

• Topics

2
A Topics
3
Primitive Types

• int
• double
• boolean

4
Operators

• , -, , /,
• , --
• , -, , /,
• , !, lt, gt, lt, gt
• , , !

5
Numeric Casts

• (int)
• (double)

6
String Concatenation

• will convert numbers to strings and invoke the
  toString() method on objects

7
Escape Sequences

• \\
• \
• \n

8
Input Output

• INPUT IS NOT TESTED
• Output is restricted to System.out.print and
  println
• Formatting output is not tested

9
Arrays

• One-dimensional
• Arrays of primitive types of objects
• Initialization of named arrays
• int array 1, 3, 6, 9

10
Control Structures

• if
• if/else
• while
• for
• return
• (do/while, switch, continue, break not tested)

11
Method Overloading

• Understand signature of method
• Depends on number, types order of parameters
• Does not depend on return type of method

12
Classes

• Construct objects with new operator
• Supply constructor parameters
• Invoke accessor modifier methods
• Modify existing classes
• Design own classes

13
Visibility

• All classes will be public
• All instance variable will be private
• Methods, constructors and constants are either
  public or private
• NO protected

14
Comments

• // single line comments
• / / block comments
• No Javadoc comments

15
Final Static

• final keyword is used for final block scope
  constants
• static final class scope constants
• static methods
• static final variables
• NO final parameters, final methods, final
  classes, static variables

16
null this

• null reference is in the Java subset
• this is restricted to passing an implicit
  parameter in its entirety to another method
  (obj.method(this))
• Descriptions such as the implicit parameter this

17
Super

• Use to invoke superclass constructor
• ex super(args)
• Or to invoke superclass method
• ex super.method(args)

18
Constructors

• Be able to implement
• Initialize all instance variables
• Dont need to know default rules

19
Extend Implement

• extend classes
• implement interfaces
• Know inheritance!!!

20
Read and Understand

• Be able to read definitions of interfaces and
  abstract classes
• Understand that the abstract methods need to be
  redefined for non-abstract classes
• Write interfaces or class declarations when given
  a general description of the interface or class

21
Equals

• Know when to use or .equals
• Objects equals
• Identity

22
Subclass to Superclass

• No casting is needed to convert from a subclass
  to a superclass
• Do need to know class casts
• ArrayList xx new ArrayList()
• yy (yyclass)xx.get(i)

23
Packages

• import statement
• import package.subpackage.class

24
Exceptions

• NullPointerException
• ArrayIndexOutOfBoundsException
• ArithmeticException
• ClassCastException
• IllegalArgumentException

25
Standard Library Methods

• java.lang.Object
• equals
• toString
• java.lang.Comparable
• compareTo
• java.lang.Integer
• Integer(int value) //constructor
• intValue
• equals
• toString
• compareTo

26
Standard Library Methods (contd)

• java.lang.Double
• Double(double value) //constructor
• doubleValue
• equals
• toString
• compareTo
• java.lang.String
• compareTo
• equals
• length
• substring
• indexOf

27
Standard Library Methods (contd)

• java.lang.Math
• abs (for int and double)
• pow
• sqrt
• java.util.Random
• nextInt
• nextDouble

28
Standard Library Methods (contd)

• java.util.ArrayList
• size
• add
• get
• set
• remove

29
AB Topics
30
Two-dimensional Arrays

• Ragged arrays are not tested
• int x new int3
• Dont need to know int33 is an array of
  arrays
• Know that x0.length is the number of columns in
  a rectangular two-dimensional array named x

31
Abstract Classes

• AB students are expected to design own interfaces
  and abstract classes

32
Throwing Unchecked Exceptions

• IllegalStateException
• NoSuchElementException

33
Standard Library Methods

• java.lang.Object
• equals
• toString
• hashCode
• java.lang.Comparable
• compareTo
• java.lang.Integer
• Integer(int value) //constructor
• intValue
• equals
• toString
• compareTo

34
Standard Library Methods (contd)

• java.lang.Double
• Double(double value) //constructor
• doubleValue
• equals
• toString
• compareTo
• java.lang.String
• compareTo
• equals
• length
• substring
• indexOf

35
Standard Library Methods (contd)

• java.lang.Math
• abs (for int and double)
• pow
• sqrt
• java.util.Random
• nextInt
• nextDouble

36
Standard Library Methods (contd)

• java.util.List
• add
• size
• get
• set
• iterator
• listIterator
• java.util.ArrayList
• All List methods
• add
• remove

37
Standard Library Methods (contd)

• java.util.LinkedList
• addFirst
• addLast
• getFirst
• getLast
• removeFirst
• removeLast

38
Standard Library Methods (contd)

• java.util.Set
• add
• contains
• remove
• size
• iterator
• java.util.HashSet
• java.util.TreeSet

39
Standard Library Methods (contd)

• java.util.Map
• put
• get
• remove
• containsKey
• size
• keySet
• java.util.HashMap
• java.util.TreeMap

40
Standard Library Methods (contd)

• java.util.Iterator
• hasNext
• next
• remove
• Java.util.ListIterator
• add
• set

41
Online resources

• Acorn online
• Java API