THE CLASSICAL ---> Exception in thread "main" java.lang.NoSuchMethodError: main

Question

Possible Duplicate:
Exception in thread “main” Java.lang.NoSuchMethodError: main ??

public class InsertionSort
{
public static void main ( int[] a)
{
    int j;
    for( int p=1 ; p<a.length ; p++)
    {
        int tmp = a[p];
        for( j=p ; j>0 && tmp<a[j-1] ; j--)
        {
            a[j] = a[j-1];
        }
        a[j] = tmp;
    }
}
}

And this happens in Terminal. (I'm on a Mac if it matters) javac InsertionSort.java;java InsertionSort Exception in thread "main" java.lang.NoSuchMethodError: main

score 3 · Answer 1 · answered Feb 08 '11 at 21:33

You need a proper main() to make the class runnable. A main method should have an array of string as the only argument, you have an array of ints.

So, to solve it, redeclare it to "public static void main(String[] args)" and do the integer parsing in the method. Neither java nor the OS will do that conversion for you.

score 1 · Answer 2 · answered Feb 08 '11 at 21:33

1

public static void main (String[] arg)

main accepts array of string, not array of int.

answered Feb 08 '11 at 21:33

x.509

2,205
10
44
58

score 1 · Answer 3 · answered Feb 08 '11 at 21:34

1

The JVM lookt for a public static void main(String[]) signature, not for a main method that takes an int[] as argument.

answered Feb 08 '11 at 21:34

rsp

23,135
6
55
69

score 1 · Answer 4 · answered Feb 08 '11 at 21:37

It will run if you do it like this:

public static void main ( String[] args)
{
    int[] a = new int[args.length];
    for(int i = 0; i < args.length; i++){
        a[i]=Integer.parseInt(args[i]);
    }
    int j;
    for( int p=1 ; p<a.length ; p++)
    {
        int tmp = a[p];
        for( j=p ; j>0 && tmp<a[j-1] ; j--)
        {
            a[j] = a[j-1];
        }
        a[j] = tmp;
    }
}

A main method, needs a String array, you need an int array, so we'll just convert the one to the other.

THE CLASSICAL ---> Exception in thread "main" java.lang.NoSuchMethodError: main

4 Answers4