Exception in thread main error

Question

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Causes of 'java.lang.NoSuchMethodError: main Exception in thread “main”'

I'm hoping this is just a simple error here, I've looked up numerous other instantces of people getting the same error message but none of their solutions really seem to apply for me. I was just wondering if you guys could help me find the error in my code. I'm not even sure if it's functional because I can't get it to run, so I suppose it could be a logic error.

When I try to run the following cold I am met with fatal exception error occured. Program will exit.

Eclipse also gives me: java.lang.NoSuchMethodError: main Exception in thread "main"

Thank you very much for any assistance you can offer!

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;



public class JoPuzzle
{

public static Integer main(String[] args)
{
    Scanner input = new Scanner(System.in);

    System.out.println("Please enter the number of soliders");
    int soldiers = input.nextInt();
    System.out.println("Please enter the how many soldiers are skipped before the next death");
    int count = input.nextInt();

     List<Integer> soldiersList = new ArrayList<Integer>(soldiers);
      for (int i = 1; i <= count; i++) {

    soldiersList.add(i);

  }



  int currentIndex = 0;

  while(soldiersList.size() > 1) {

      currentIndex = (currentIndex - 1 + count) % soldiersList.size();

      soldiersList.remove(currentIndex);

  }

  return soldiersList.get(0);

  }   //end main

}//end class

When the program runs, the JVM will check for a method main with signature public static void, which is not present in yours. How is it even starting the execution? — Anuj Balan, Mar 12 '12 at 05:14

score 2 · Answer 1 · answered Mar 12 '12 at 05:14

2

The signature for main method is
public static void main(String[] args).

When you run your program the JVM will look for this method to execute. You need to have this method in your code

answered Mar 12 '12 at 05:14

Ashwini Raman

726
1
6
11

Oh wow, yes I changed it initially by trying to get rid of the error on my return soldiersList.get(0) instead of simply printing it. Thanks that should have been obvious. I need sleep -_- – Sh0gun Mar 12 '12 at 05:17

Sumit Singh · Accepted Answer · 2012-03-12T05:57:24.420

2

We know that to execute any java Program we should have a main function. because this is a self callable by JVM. And the signature of the function must be..

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

but in your code it's seem like this...

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

so its consider as a different function , so change your main return type..

edited Mar 12 '12 at 05:57

answered Mar 12 '12 at 05:39

Sumit Singh

23,530
8
71
99

score 0 · Answer 3 · answered Mar 12 '12 at 05:15

0

Your program does not contain the main method, change it to

public static void main(String[] args)

If you want to return an Integer object, then define a custom mehod and call that method inside the main method and handle that returned value.

answered Mar 12 '12 at 05:15

Chandra Sekhar

16,511
14
71
109

Or you can exit with a status code to define if the program completed successfully (usually a status of 0) or an error occurred with any other integer you like with System.exit(0); – Dan675 Mar 12 '12 at 05:28

score 0 · Answer 4 · answered Mar 12 '12 at 05:18

0

Java main() function doesn't have a return-statement. This line

public static Integer main(String[] args)

should be

public static void main(String [] args)

Also since it has no return value, you should delete the return statement.

answered Mar 12 '12 at 05:18

user1263270

51
1
8

score 0 · Answer 5 · answered Mar 12 '12 at 05:20

0

Java's main method should have below signature.

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

answered Mar 12 '12 at 05:20

Balaswamy Vaddeman

7,634
3
28
40

score 0 · Answer 6 · answered Mar 12 '12 at 05:21

Try to run this code and tell if it works.

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


public class JoPuzzle
{

public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);

    System.out.println("Please enter the number of soliders");
    int soldiers = input.nextInt();
    System.out.println("Please enter the how many soldiers are skipped before the next death");
    int count = input.nextInt();

     List<Integer> soldiersList = new ArrayList<Integer>(soldiers);
      for (int i = 1; i <= count; i++) {

    soldiersList.add(i);

  }



  int currentIndex = 0;

  while(soldiersList.size() > 1) {

      currentIndex = (currentIndex - 1 + count) % soldiersList.size();

      soldiersList.remove(currentIndex);

  }

 // return soldiersList.get(0);

  System.out.println(soldiersList.get(0));
  }   //end main

}//end class

Exception in thread main error

6 Answers6