Create packages, import packaged classes and interfaces into your programs, move packages, and encapsulate them in jar files.

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.

There is a reason why Java method modifiers exist. If you call public methods internally and don't understand why, your developers could face major class issues.

The difference between abstract classes and interfaces has long vexed Java developers. Find out how Java 8's default methods introduce both new complexity and new options to that familiar ...