哪位高手可以支援点java题目

谁可以支援点java题目
谁有比较经典的java题目。发来做做。。 还有答案一起。。。
 不知道做的时候可以看答案。。

[解决办法]
thinking in java里有很多经典题目：举例一个
从基本的咖啡入手，创建一个简单的装饰器系统，然后提供刻意导入牛奶，泡沫，巧克力，焦糖和生奶油的装饰器

Java code

// generics/CoffeeDecoration38.java// TIJ4 Chapter Generics, Exercise 38, page 719// Create a simple Decorator system by starting with basic coffee, then// providing decorators of steamed milk, foam, chocolate, caramel and // whipped cream.import java.util.*;class BasicCoffee {    private static long counter = 0;      private final long id = counter++;    private String value;    public void set(String val) { value = val; }    public String get() { return value; }      public String toString() {            return getClass().getSimpleName() + " " + id;      }}class Decorator extends BasicCoffee {    protected BasicCoffee basicCoffee;    public Decorator(BasicCoffee basicCoffee) {         this.basicCoffee = basicCoffee;     }    public void set(String val) { basicCoffee.set(val); }    public String get() { return basicCoffee.get(); }}class SteamedMilk extends Decorator {    private final String steamedMilk = "steamedMilk";    public SteamedMilk(BasicCoffee basicCoffee) {        super(basicCoffee);    }    public String getSteamedMilk() { return steamedMilk; }}class Foam extends Decorator {    private final String foam = "foam";    public Foam(BasicCoffee basicCoffee) {        super(basicCoffee);    }    public String getFoam() { return foam; }}class Chocolate extends Decorator {    private final String chocolate = "chocolate";    public Chocolate(BasicCoffee basicCoffee) {        super(basicCoffee);    }    public String getChocolate() { return chocolate; }}class Caramel extends Decorator {    private final String caramel = "caramel";    public Caramel(BasicCoffee basicCoffee) {        super(basicCoffee);    }    public String getCaramel() { return caramel; }}class WhippedCream extends Decorator {    private final String whippedCream = "whippedCream";    public WhippedCream(BasicCoffee basicCoffee) {        super(basicCoffee);    }    public String getWhippedCream() { return whippedCream; }}public class CoffeeDecoration38 {    public static void main(String[] args) {        SteamedMilk sm = new SteamedMilk(new BasicCoffee());        SteamedMilk sm2 = new SteamedMilk(            new Foam(new BasicCoffee()));        Chocolate c = new Chocolate(new BasicCoffee());        WhippedCream wc = new WhippedCream(new Caramel(            new Chocolate(new Foam(new SteamedMilk(            new BasicCoffee())))));    }}
[解决办法]
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[解决办法]
class A {
private String a;//1
public A() {//2
}
}

class B extends A {
private string b;//3
public B()//4 {
}
}

main() {
B b = new B();
}

b的初始化时，上面标识的1,2,3,4的执行顺序