java接口、继承、多态

public class Test extends Object{

    public Test(){

    }

    protected void doSomething(){

    }

    protected Test dolt(){
        return new Test();
    }

}

public class Test2 extends Test {

    public Test2(){
        super();
        super.doSomething();
    }

    public void doSomethingNew(){

    }

    public void doSomething(){

    }

    protected Test2 dolt(){
        return new Test2();
    }
}

public class Test3 {
    public String toString(){
        return "this is"+getClass().getName()+"class write is tostring() 方法";
    }

    public static void main(String[] args) {
        System.out.println(new Test3());
    }
}

public class Test4 {
}

public class Test5 {
    public static void main(String[] args) {
        String s1 = "123";
        String s2 = "123";
        System.out.println(s1.equals(s2));
        Test4 v1 = new Test4();
        Test4 v2 = new Test4();
        System.out.println(v1.equals(v2));
    }
}

public class Test6 {
    public static void draw(Test7 test7) {
        System.out.println("this is test6");
    }
}

public class Test7 extends Test6{
    public static void main(String[] args) {
        Test7 test7 = new Test7();
        draw(test7);
    }
}

/**
 * 重载
 */
public class Test8 {
    public static int add(int a) {
        return a;
    }

    public static int add(int a,int b) {
        return a+b;
    }

    public static int add(int a,double b) {
        return 1;
    }

    public static int add(int ...a) {
        int len = a.length;
        int s = 0;
        for (int i = 0; i < len; i++) {
            s += a[i];
        }
        return s;
    }

    public static void main(String[] args) {
        System.out.println("add (int a)"+add(1));
        System.out.println("add (int a,int b)"+add(1,2));
        System.out.println("add (int a,double b)"+add(1,2.11));
        System.out.println("add (int ...a)"+add(1,2,3,4,5,6));

    }
}

/**
 * 多态
 */
public class Test9 {
    int num = 0;
    public void draw(Test9 test9) {
        System.out.println(num);
        num++;
    }

    public static void main(String[] args) {
        Test9 test9 = new Test9();
        test9.draw(new Test10());
        test9.draw(new Test11());
    }
}

public class Test10 extends Test9{
    public Test10(){
        System.out.println("This is Test 10");
    }
}

public class Test11 extends Test9 {
    public Test11(){
        System.out.println("This is Test11");
    }
}

/**
 * 接口
 */
interface Test12 {
    public void draw();
}

public class Test13 {
    public void doAnyThing(){

    }

    public static void main(String[] args) {
        Test14 test14 = new Test14();
        Test15 test15 = new Test15();

        test14.draw();
        test15.draw();

        Test13 test13 = new Test13();
        test13.doAnyThing();
    }
}

public class Test14 extends Test13
        implements Test12 {
    public void draw(){
        System.out.println("this is This14");
    }
    public void doAnyThing(){

    }
}

public class Test15 extends Test13 implements Test12 {
    public void draw(){
        System.out.println("this is Test 15");
    }

    public void doAnyThing(){

    }
}