class B{
    int x=100,y=200;
    public void setX(int x){ x=x; }
    public void setY(int y){ this.y=y; } 
    public int getXYSum(){ return x+y; } 
 } 
 public class A { 
    public static void main(String args[]){
        B b=newB(); 
        b.setX(-100); 
        b.setY(-200); 
        System.out.println("sum="+b.getXYSum()); 
    } 
 } 

public class Main{ 
    public static void main(String[]args){ 
        System.out.println("创建一个Faculty对象"); 
        new Faculty(); 
    } 
} 
class Faculty extends Employee { 
    public Faculty(){ 
        System.out.println("完成Faculty的任务"); 
    } 
} 
class Employee extends Person{ 
    public Employee(){ 
        this("调用Employee的重载构造方法"); 
        System.out.println("完成Employee的任务"); 
    } 
    public Employee(String s){ 
        System.out.println(s); 
    } 
} 
class Person { 
    public Person() { 
        System.out.println("完成Person的任务"); 
    } 
}

public class Main{
  static{
     System.out.print("Hi here,");
  }
  public void print(){
     System.out.print("Hello");
  }
  public static void main(String args[]){
     Main m1=new Main();
     m1.print();
     Main m2=new Main();
     m2.print();
  }
}

public class Test {
    public int t=4;
    public static void main(String[] args) {
        new Test().NumberPlay();
    }
    public void NumberPlay() {
        int t=2;
        t = t+5;
        this.t = this.t-2;
        t = t-this.t;
        System.out.println(t+this.t+"ok");
    }
}

class A{``
  String name="A";
  String getName(){
     return name;
  }
  String greeting(){
     return "class A"; 
  }
}
class B extends A{
  String name="B";
  String greeting(){
     return "class B";
  }
}
public class Main{
  public static void main(String args[]){
     A a=new A();
     A b=new B();
     System.out.println(a.greeting()+" has name "+a.getName());
     System.out.println(b.greeting()+" has name "+b.getName());
  }
}

class Shape {
     private String strColor;
     public Shape() {
           System.out.println("我是图形");
       }
 public Shape(String strColor) {
        System.out.println("我是"+strColor+"的图形");
 }
 public void printType() {
       System.out.println("我是"+strColor+"的图形");
 }
 public void printName(){
       System.out.println("我不知道我叫什么");
 }
}
class Circle extends Shape{
     private String strColor,strName;
      public Circle() {
            System.out.println("我是圆");
      }
 public Circle(String strColor,String strName) {
      super(strColor);
      this.strName = strName;
       System.out.println("我是"+strColor+"的圆");
 }
 @Override
 public void printName(){
       System.out.println("我叫"+strName);
 }
}
public class Test {
     public static void main(String[] args)  {
         String strColor = "红色";
         String strName = "圆圆";
         Shape shape1 = new Shape();
         shape1.printName();
         shape1 = new Circle(strColor,strName);
         shape1.printName();
     }
}

（1）我是图形
（2）我是红色的图形
（3）我是圆
（4）我是红色的圆
（5）我不知道我叫什么
（6）我叫圆圆

class A {
    public int data=5;
    public void print() { 
        System.out.println(data);
    }
}
class B extends A {
    public int data=2;
    public void print() {
        System.out.println(data);
    }
}
public class Main {
    public static int data=3;
    public static void main(String[] args) {
        A a = new A();
        a.print();
        System.out.println(a.data);
        A b = new B();
        b.print();
        System.out.println(b.data);
        System.out.println(Main.data);
    }
}

public class Test extends TT{ 
    public static void main(String args[]){ 
        Test t=new Test("Tom"); 
    } 
    public Test(String s){ 
        super(s); 
        System.out.println("How do you do?"); 
    } 
    public Test(){ 
        this("I am Tom"); 
    } 
} 
class TT { 
    public TT(){ 
        System.out.println("What a pleasure!"); 
    } 
    public TT(String s){ 
        this(); 
        System.out.println("I am "+s); 
    } 
} 

class People {
String name;
public People() {
System.out.print(1);
}
public People(String name) {
System.out.print(2);
this.name = name;
}
}
class Child extends People {
People father;
public Child(String name) {
System.out.print(3);
this.name = name;
father = new People(name + ":F");
}
public Child(){
System.out.print(4);
}
}

public class Test {
  public static void main(String[] args) {
     new Circle9();
  }
}
abstract class GeometricObject {
  protected GeometricObject() {
    System.out.print("A");
  }
  protected GeometricObject(String color, boolean filled) {
    System.out.print("B");
  }
}
class Circle9 extends GeometricObject {
  /** No-arg constructor */
  public Circle9() {
    this(1.0);
    System.out.print("C");
  }
  /** Construct circle with a specified radius */
  public Circle9(double radius) {
    this(radius, "white");
    System.out.print("D");
  }
  /** Construct circle with a specified radius and color */
  public Circle9(double radius,String color) {
    this(radius, "white", false);
    System.out.print("E");
  }
  /** Construct a circle with specified radius, filled, and color */
  public Circle9(double radius, String color, boolean filled) {
    super(color, filled);
    System.out.print("F");
  }
}

class A{ 
    int i=7; 
    public A(){ 
        setI(20); 
        System.out.println("i="+i); 
    } 
    public void setI(int i){
        this.i=2*i;
    } 
}
class B extends A{ 
    public B(){ 
        System.out.println("i="+i); 
    } 
    public void setI(int i){
        this.i=3*i;
    } 
} 
public class Main{ 
    public static void main(String[] args){ 
        new A(); 
        new B(); 
    } 
}