java.lang: A collection of language-related classes, such as Object and String, organized in the java package’s lang subpackage; java.lang.ref: A collection of reference-related language classes ...

Atomic classes are a part of the java.util.concurrent.atomic package, which was introduced in Java 5 to support low-level concurrency and synchronization.

Strictly speaking, it isn't possible to list the classes in a package. This is because a package is really nothing more than a namespace (eg com.epicapplications.foo.bar), and any jar-file in the ...

Classes and objects in Java must be initialized before they are used. You’ve previously learned that class fields are initialized to default values when classes are loaded, and that objects are ...

Sealed classes make Java an even more powerful and expressive language and set the stage for even more sophisticated techniques such as pattern matching, which we'll explore in a subsequent article. A ...