Java compilation of a .java file without a public class

Question

Okay, so a java source file must have at least one public class and the file should be called \"class-name.java\". Fair enough.

Hence, if I have a class, th

Answer 1

You can place non-public class in a file, and it's not a bug but feature.

Your problem is on level of packaging, not compile. Because you can compile this file with non-public class, but you can't call it from outside, so it's not working as application base class

Like this:

// [+] single file: SomeWrapper.java 

public class SomeWrapper {
    ArrayList<_PrivateDataType> pdt;
}
// [-] single file: SomeWrapper.java 

// [+] single file: _PrivateDataType.java 
class _PrivateDataType {
    // members, functions, whatever goes here
}

// [-] single file: _PrivateDataType.java