棘手的Java程序

Question

Look at the code below and please help me solve the trick.

class TestTrick{

    public static void main(String args[])
    {

    }

    static marker()
    {

    System.out.println("programe executed");

    }

}

The result required from this program is that the program should print program executed , meaning that the marker method should be executed. But there are some rules:

1. Nothing should be written in both the methods.
2. No other class can be added to the program.
3. The program must execute the output statement in the marker method.

It's been three days and I am unable to solve the problem because I am not a Java programmer. I have searched everything on internet to get a clue but I failed. Please someone help me run this program by strictly following the rules.

Answer 1

I think what they're looking for is a static initializer .

static {
    marker();
}

This gets run when the class is loaded.

Answer 2

The problem is that you don't want a method for your marker - you just want a static initialization block:

class Trick {
    // not a method, just something to execute when the class is loaded
    static { System.out.println("executed"); }

    public static void main(String[] args) {

    }

}

Results: http://ideone.com/bQAgT

If you've been provided the code already (which I'm not sure you have because static marker() isn't valid code) then you can simply call marker() from your static block.

Answer 3

you can use static initializer, that will be executed before the Main method can be run.

static {
     marker();
}

Answer 4

The static block will do the trick for you. But you have a syntax error in your program. Since marker is a method, it must have a return type. I am assuming void .

class testTrick {

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

    static void marker() {
        System.out.println("programe executed");
    }

    static {
        marker();
    }
}

Answer 5

This is easy. In the class add a static constructor to call the marker method and then in the constructor put in a system.exit

Answer 6

An even trickier program is

class testTrick {
    static { marker(); System.exit(0); } static void marker() {
        System.out.println("program executed");
    }
}

Note: marker has to provide a return type eg void or it won't compile. You can keep the main() method if you like, but it is never called.

The static initialiser is called before the main method so it can call another method and it can exit before you see a message saying no main() method found.

Answer 7

does this follow your rules ?, creating a static block will always execute as it gets stored along with the class files and it doen need a main method to call

class TestTrick{

    public static void main(String args[])
    {

    }

    static marker()
    {

    System.out.println("programe executed");

    }

}

Answer 8

public class M
{
    public static void main(String[] args)
    {

    }
    static
    {
        marker();
    }
    public static void marker()
    {
         System.out.println("Done");
    }
}

Answer 9

class TestTrick{
public static void main(String args[])
{

}

static{
    marker();}
static void marker(){

System.out.println("programe executed");

}

Look at the requirements. You can do anything you want as long as you do not alter the methods.

So a static block(which will always execute in a program) is needed. Its not a method, and you can call marker() from there(which btw needs to be assigned a return type)

Answer 10

class testTrick
{

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

    static 
    {
        marker();
    }

    static void marker()
    {
        System.out.println("programe executed");
    }
}

Answer 11

int i = 10 + + 11 - - 12 + + 13 - - 14 + + 15;

System.out.println(i);

Answer 12

You would need to call the marker method in the main method ie; something like this:

class testTrick {

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

    static void marker() {
        System.out.println("programe executed");
    }

}