3 (JAVA)

3(JAVA)1Java1Sun Microsystems1991

/

2Java Virtual Machine (JVM)

CPU

3Java Virtual Machine (JVM)

JVM4Java Virtual MachineCPUJava2 -- JVM -- Web

Java 2 Platform Standard Edition Development Kit (JDK)

5336

7

8ABDEFCGObjectDAAD

19ABCgetArea()getArea()getArea()Java

10java.appletjava.awtAbstract Window Toolkit (AWT)java.awt.eventAWTjava.awt.imagejava.beansJavaBeansBeansjava.iojava.langJavaJava 2 Platform Standard Edition Development Kit 5.0 (JDK)

JDK 6.0

11Java

12class Example1 {public static void main (String args[]) {System.out.println(This is the output from Example1);}}>Javac Example1.javaThis is the output from Example1Java813char16Unicodebooleanbyte8short16int32long64float32double64

14class Example2 {public static void main (String args[]) {int i = 50;System.out.println(The value of i is + i);}}>Javac Example2.javaThe value of i is 50()\+

15String s = abcde + ef \ ghi \ ;16+-*/%+=-=++1

1717int i;float f;i= 10f = 23.25fSystem.out.println(i * f);

(type)value18int b;int i = 258;b = (byte)i;System.out.println(i * f);

///**//**3*/2191

1

1

120type varName[];varName = new type[size];type varName[] = new type[size];11

1

21varName.length;type varName[] = {e0, , en};int ia[] = new int[10]ia[2]ia[3]ia[4]ia[5]ia[6]ia[7]ia[8]ia[9]ia[1]ia[0]22int ib[][] = new int[2][2]; ib[0][0]ib[1][0]ib[0][1]ib[1][1]JavaJavaAbstract, boolean, etc......23