kyoto dreams: January 2006

kyoto dreams

Wednesday, January 11, 2006

Transformed Given the code below. Will it compile?


\u0070\u0075\u0062\u006c\u0069\u0063\u0020\u0063\u006c\u0061\u0073\u0073\u0020\u0053\u0077\u0061\u0070\u0070\u0065\u0072\u0020\u007b
\u000a\u0020\u0020\u0020\u0020\u0070\u0075\u0062\u006c\u0069\u0063\u0020\u0073\u0074\u0061\u0074\u0069\u0063\u0020\u0076\u006f\u0069\u0064\u0020\u006d\u0061\u0069\u006e\u0028\u0053\u0074\u0072\u0069\u006e\u0067\u005b\u005d\u0020\u0061\u0072\u0067\u0073\u0029\u0020\u007b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0049\u006e\u0074\u0065\u0067\u0065\u0072\u0020\u006e\u0031\u0020\u003d\u0020\u006e\u0065\u0077\u0020\u0049\u006e\u0074\u0065\u0067\u0065\u0072\u0028\u0032\u0036\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0049\u006e\u0074\u0065\u0067\u0065\u0072\u0020\u006e\u0032\u0020\u003d\u0020\u006e\u0065\u0077\u0020\u0049\u006e\u0074\u0065\u0067\u0065\u0072\u0028\u0033\u0039\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0053\u0079\u0073\u0074\u0065\u006d\u002e\u006f\u0075\u0074\u002e\u0070\u0072\u0069\u006e\u0074\u006c\u006e\u0028\u006e\u0031\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0053\u0079\u0073\u0074\u0065\u006d\u002e\u006f\u0075\u0074\u002e\u0070\u0072\u0069\u006e\u0074\u006c\u006e\u0028\u006e\u0032\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0073\u0077\u0061\u0070\u0028\u006e\u0031\u002c\u0020\u006e\u0032\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0053\u0079\u0073\u0074\u0065\u006d\u002e\u006f\u0075\u0074\u002e\u0070\u0072\u0069\u006e\u0074\u006c\u006e\u0028\u006e\u0031\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0053\u0079\u0073\u0074\u0065\u006d\u002e\u006f\u0075\u0074\u002e\u0070\u0072\u0069\u006e\u0074\u006c\u006e\u0028\u006e\u0032\u0029\u003b
\u000a\u0020\u0020\u0020\u0020\u007d
\u000a\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0073\u0074\u0061\u0074\u0069\u0063\u0020\u0076\u006f\u0069\u0064\u0020\u0073\u0077\u0061\u0070\u0028\u004f\u0062\u006a\u0065\u0063\u0074\u0020\u006f\u0031\u002c\u0020\u004f\u0062\u006a\u0065\u0063\u0074\u0020\u006f\u0032\u0029\u0020\u007b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u004f\u0062\u006a\u0065\u0063\u0074\u0020\u0074\u006d\u0070\u0020\u003d\u0020\u006f\u0031\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u006f\u0031\u0020\u003d\u0020\u006f\u0032\u003b
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020
\u000a\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u0020\u006f\u0032\u0020\u003d\u0020\u0074\u006d\u0070\u003b
\u000a\u0020\u0020\u0020\u0020\u007d
\u000a\u007d

¶ 1:03 PM 0 comments

Caster 3 Given the class below. Will it compile?

If so, what's the output?

If not, how would you fix it?


public class Caster3 {
    public static void main(String[] args) {
        Object i = new Integer(32); 
        Integer o = (Integer) i;

        out((Object) o);
    }

    static void out(Object o) {
        System.out.println("Object out");
    }

    static void out(Integer i) {
        System.out.println("Integer out");
    }
}

¶ 12:46 PM 0 comments

Caster2 Given the following class. Will it compile?

If so, what's the output?

If not, how would you fix it?


public class Caster2 {
    public static void main(String[] args) {
        Object i = new Integer(32); 
        Integer o = (Integer) i;

        out(o);
    }

    static void out(Object o) {
        System.out.println("Object out");
    }

    static void out(Integer i) {
        System.out.println("Integer out");
    }
}

¶ 12:44 PM 0 comments

Test Consider the class below.

Will it compile?

If it would, what is the output?

If not, how would you fix it?


public class Test {
    public static void main(String[] args) {
        if (false) {
            System.out.println("world peace");
        }
        
        while (false) {
            System.out.println("fair and balanced");
        }
    }
}

¶ 10:57 AM 0 comments

Finally Given the code below. What is the output?


public class Finally {
    public static void main(String[] args) {
        foo();
    }
    
    static void foo() {
        try {
            System.out.println("try");
            System.exit(0);
        }
        finally {
            System.out.println("finally");
        }
    }    
}

¶ 10:53 AM 0 comments

Invoke2 Consider the code below. What is the output?


public class Invoke2 {
    public static void main(String[] args) {
        Integer o = new Integer(47);
        
        out(o);
    }
    
    static void out(Object o) {
        System.out.println("Object out");
    }

    static void out(Integer i) {
        System.out.println("Integer out");
    }
}

¶ 7:54 AM 0 comments

Caster Consider code below.

Will it compile?

If so what is the output?

If not, how would you fix it?


public class Caster {
    public static void main(String[] args) {
        Integer o = (Integer) new Object();

        out(o);
    }

    static void out(Object o) {
        System.out.println("Object out");
    }

    static void out(Integer i) {
        System.out.println("Integer out");
    }
}

¶ 7:53 AM 0 comments

Invoke Consider the code below. What's the output.


public class Invoke {
    public static void main(String[] args) {
        Object o = new Integer(47);
        
        out(o);
    }
    
    static void out(Object o) {
        System.out.println("Object out");
    }

    static void out(Integer i) {
        System.out.println("Integer out");
    }
}

¶ 7:40 AM 0 comments

Swapper Consider the code below. What is the output.


public class Swapper {
   public static void main(String[] args) {
       Integer n1 = new Integer(26);
       Integer n2 = new Integer(39);
              
       System.out.println(n1);
       System.out.println(n2);
              
       swap(n1, n2);
      
       System.out.println(n1);
       System.out.println(n2);
   }
  
   static void swap(Object o1, Object o2) {
       Object tmp = o1;
      
       o1 = o2;
      
       o2 = tmp;
   }
}

¶ 7:01 AM 0 comments

Friday, January 06, 2006

Three The following code compiles and runs, but only 1 thread is ever created. What is the problem and how would you fix it?


public class T extends Thread {
    public static void main(String []args) {
        for (int i = 0; i < 10; i++) {
            T t = new T();
            t.run();
        } 
    }



    public void run() {
        while (true) {
            System.out.println(System.currentTimeMillis());

            try {
                Thread.sleep(1000);
            }
            catch (InterruptedException e) {}
        }
    }
}

¶ 8:50 AM 0 comments

Thursday, January 05, 2006

Two Consider the code below.

When run, what is the output and why?



public class A {
    private int count = 1;


    public static void main(String []args) {
        B b = new A().new B();
    }

    class B {
        private int count = 2;

        B() {
            System.out.println(count);
        }
    }
}

¶ 12:28 PM 0 comments

One Consider the code below.

1. Will it compile?
2. If so what is the output?
3. If not, why not, and how would you fix it?


public class Foo {
  private int count = 1;

  public static void main(String []args) {
    new Bar();       
  }
}

class Bar extends Foo {
  public Bar() {
    System.out.println(count);
  }
}

¶ 7:57 AM 0 comments

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