Section 8.1.3 of the Java Language Specification (JLS) states, “The class java.lang.Object … is the primordial class and has no direct superclass.” That means java.lang.Object serves as the root class ...
The release of Java SE 15 in Sept 2020 will introduce "sealed classes" (JEP 360) as a preview feature. A sealed class is a class or interface which restricts which other classes or interfaces may ...