کلیدواژه ی استاتیک در جاوا

public class Log{

  public static String label = "Log";

}
        

public static void main(String[] args){
    System.out.println(label);
}
        

class MyClass{

    private Type myMemberField;

    private Type1 myStaticField;

    public myMemberMethod(){
        ...
    }

    public static myStaticSecondMethod(){
        ...
    }

    public static myStaticMethod(){
        //خطای کامپایل
        myMemberField = ...;

        //خطای کامپایل
        myMemberMethod();

        //بدون خطا
        myStaticField = ...;

        //بدون خطا
        myStaticSecondMethod();
    }

}
                        

public class Circle {
    double radius;

    private static int numberOfObjects = 0;

    public Circle(){
        this.radius = 1;
        numberOfObjects ++;
    }

    public Circle(double radius){
        this.radius = radius;
        numberOfObjects++;
    }

    public double getArea(){
        return radius * radius * Math.PI;
    }

    public static int getNumberOfObjects(){
        return Circle.numberOfObjects;
    }

}
                        

public class TestCircle {

    public static void main(String[] args){
        System.out.println("Before creating new instance from Circle number of objects are " +
        Circle.getNumberOfObjects());

        Circle c0 = new Circle(4);
        System.out.println("After creating c0: (radius: " + c0.radius + ", " + "area: " + c0.getArea() + ")"
        + " number of objects are " + Circle.getNumberOfObjects());

        Circle c1 = new Circle();

        System.out.println("After creating c1: (radius: " + c1.radius + ", " + "area: " + c1.getArea() + ")"
        + " number of objects are " + Circle.getNumberOfObjects());
    }
}
                        

public class TV {
    public static final int MAXIMUM_VOLUME_LEVEL = 10;
    public static final int MINIMUM_VOLUME_LEVEL = 0;

    public static final int MAXIMUM_CHANNEL_NUMBER = 120;
    public static final int MINIMUM_CHANNEL_NUMBER = 1;

    private String panel;
    private int channel = 1;
    private int volume = 1;
    private boolean on;

    public TV(String panel){
        this.panel = panel;
    }

    public TV(){
        this("FLATIRON");
    }

    public void turnOn(){
        on = true;
    }

    public void turnOff(){
        on = false;
    }

    public void setChannel(int channel) {
        if (on && channel >= MINIMUM_CHANNEL_NUMBER && channel <= MAXIMUM_CHANNEL_NUMBER)
        this.channel = channel;
    }

    public void setVolume(int volume) {
        if (on && volume >= MINIMUM_VOLUME_LEVEL && volume <= MAXIMUM_VOLUME_LEVEL)
        this.volume = volume;
    }

    public String getPanel(){
        return panel;
    }

    public int getChannel() {
        return channel;
    }

    public int getVolume() {
        return volume;
    }

    public void channelUp(){
        if (on && channel < MAXIMUM_CHANNEL_NUMBER) channel++;
    }

    public void channelDown(){
        if (on && channel > MINIMUM_CHANNEL_NUMBER ) channel --;
    }

    public void volumeUp(){
        if (on && volume < MAXIMUM_VOLUME_LEVEL)
        volume++;
    }

    public void volumeDown(){
        if (on && volume > MINIMUM_VOLUME_LEVEL)
        volume --;
    }

    public boolean isOn() {
        return on;
    }

    public boolean isMuted(){
        return volume == MINIMUM_VOLUME_LEVEL;
    }

}
                        

public static void main(String[] args){

    TV tv1 = new TV();
    tv1.turnOn();
    tv1.setChannel(21);
    tv1.setVolume(4);
    TV tv2 = new TV();
    tv2.turnOn();
    tv2.channelUp();
    tv2.channelUp();
    tv2.volumeUp();

    System.out.println("tv1 has been built by " + tv1.getPanel() + " panel");
    System.out.println("tv1's channel is " + tv1.getChannel() + " and volume level is " + tv1.getVolume());

    System.out.println("tv2 has been built by " + tv2.getPanel() + " panel");
    System.out.println("tv2's channel is " + tv2.getChannel() + " and volume level is " + tv2.getVolume());

}
                        

public class MyOuterClass {
...

    public static class MyInnerClass {
        ...
    }

}
        

MyOuterClass.MyInnerClass inner = new MyOuterClass.MyInnerClass();