Keep in mind that not every JAR file is runnable. Some JAR files are just support files intended to be used by other Java apps. For a JAR file to run, the JAR itself must contain at least one class ...

Java Reflection provides a lot of information about a given class at runtime; you can easily know all its super classes, implemented interfaces, methods, constructors, fields, and so on. But in ...

Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.

Since I have done most of my coding for classes (and almost exclusively in Java), I have always just run my programs through the compiler and never had to worry about actually setting it up to run ...