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Published byLester Doyle Modified over 8 years ago
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The AP Java Subset Topics
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A Topics
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Primitive Types int double boolean
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Operators +, -, *, /, % ++, -- = +=, -=, *=, /=, %= ==, !=,, = &&, ||, !
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Numeric Casts (int) (double)
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String Concatenation + will convert numbers to strings and invoke the toString() method on objects
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Escape Sequences \\ \” \n
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Input & Output INPUT IS NOT TESTED Output is restricted to System.out.print and println Formatting output is not tested
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Arrays One-dimensional Arrays of primitive types & of objects Initialization of named arrays: – int[] array = {1, 3, 6, 9};
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Control Structures if if/else while for return (do/while, switch, continue, break – not tested)
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Method Overloading Understand signature of method Depends on number, types & order of parameters Does not depend on return type of method
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Classes Construct objects with new operator Supply constructor parameters Invoke accessor & modifier methods Modify existing classes Design own classes
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Visibility All classes will be public All instance variable will be private Methods, constructors and constants are either public or private NO protected
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Comments // single line comments /* */ block comments No Javadoc comments
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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
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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”
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Super Use to invoke superclass constructor – ex: super(args); Or to invoke superclass method – ex: super.method(args);
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Constructors Be able to implement Initialize all instance variables Don’t need to know default rules
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Extend & Implement extend classes implement interfaces Know inheritance!!!
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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
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Equals Know when to use == or.equals Objects: equals Identity: ==
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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);
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Packages import statement import package.subpackage.class;
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Exceptions NullPointerException ArrayIndexOutOfBoundsException ArithmeticException ClassCastException IllegalArgumentException
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Standard Library Methods java.lang.Object – equals – toString java.lang.Comparable – compareTo java.lang.Integer – Integer(int value) //constructor – intValue – equals – toString – compareTo
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Standard Library Methods (cont’d) java.lang.Double – Double(double value) //constructor – doubleValue – equals – toString – compareTo java.lang.String – compareTo – equals – length – substring – indexOf
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Standard Library Methods (cont’d) java.lang.Math – abs (for int and double) – pow – sqrt java.util.Random – nextInt – nextDouble
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Standard Library Methods (cont’d) java.util.ArrayList – size – add – get – set – remove
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AB Topics
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Two-dimensional Arrays Ragged arrays are not tested – int [][] x = new int[3][]; Don’t need to know int[3][3] is an array of arrays Know that x[0].length is the number of columns in a rectangular two-dimensional array named x
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Abstract Classes AB students are expected to design own interfaces and abstract classes
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Throwing Unchecked Exceptions IllegalStateException NoSuchElementException
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Standard Library Methods java.lang.Object – equals – toString – hashCode java.lang.Comparable – compareTo java.lang.Integer – Integer(int value) //constructor – intValue – equals – toString – compareTo
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Standard Library Methods (cont’d) java.lang.Double – Double(double value) //constructor – doubleValue – equals – toString – compareTo java.lang.String – compareTo – equals – length – substring – indexOf
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Standard Library Methods (cont’d) java.lang.Math – abs (for int and double) – pow – sqrt java.util.Random – nextInt – nextDouble
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Standard Library Methods (cont’d) java.util.List – add – size – get – set – iterator – listIterator java.util.ArrayList – All List methods – add – remove
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Standard Library Methods (cont’d) java.util.LinkedList – addFirst – addLast – getFirst – getLast – removeFirst – removeLast
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Standard Library Methods (cont’d) java.util.Set – add – contains – remove – size – iterator java.util.HashSet java.util.TreeSet
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Standard Library Methods (cont’d) java.util.Map – put – get – remove – containsKey – size – keySet java.util.HashMap java.util.TreeMap
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Standard Library Methods (cont’d) java.util.Iterator – hasNext – next – remove Java.util.ListIterator – add – set
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Online resources Acorn online Java API
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