PPCF - Place Public Class First

According to Sun Code Conventions for Java, the public class or interface should be the first class or interface in the file.

Wrong

class Helper {
    // some code
}

public class PPCM {
    // some code
}

Tip: Place public class or interface first

Right

public class PPCM {
    // some code
}

class Helper {
    // some code
}