Question

Java Naming rules suggests which one to be used.
This

public static final class DatabaseTable

or, this

public static final class DATABASE_TABLE

Which one is correct?

Answer 1

There is no such thing as “incorrect” here, in the sense that the Java compiler or syntax of the language does not force you to use specific naming conventions.

If we look at the old Code Conventions for the Java Programming Language document, specifically Chapter 9 – Naming Conventions, we see that classes should have CamelCaseNames:

Class names should be nouns, in mixed case with the first letter of each internal word capitalized. Try to keep your class names simple and descriptive. Use whole words-avoid acronyms and abbreviations (unless the abbreviation is much more widely used than the long form, such as URL or HTML).

It doesn’t matter if the class is a nested class (static) or if the class is final.

ALL_UPPERCASE_NAMES are for constants; static final variables (not classes).