# Java Notes

# NoSuchMethodError main

Do you get the following error message?

    Exception in thread "main" java.lang.NoSuchMethodError: main

The following are common causes.

1. File/class name mismatch. Check the file and class names -- they much match exactly, even with upper and lower case. Windows doesn't care about file names that differ only in case, but Java does. If you have trouble renaming a file to fix the case, first rename it to something different, then rename to the correct case.
2. Mistyping the main header. Something is wrong with your declaration of `main`. It must be

           public static void main(String[] args)

   Variations in the parameter declaration are allowed, but the above is what everyone expects to see.
3. CLASSPATH is a less likely cause. See CLASSPATH.