Java is a case-sensitive language, which means that identifiers differing in case are considered separate identifiers. For example, age and Age are separate identifiers. Reserved words ...

In Java, an identifier of “Hello” is not the same as “hello.” These are two separate identifiers. Every character matters. Resources and References.

The SourceVersion class provides information on Java source versions and can provide some interesting details, including demonstration of terminology covered in the Java Language Specification .