Java often appears at the top of programming languages rankings thanks to its huge popularity, rooted mainly in one thing: its “write once, run anywhere” (WORA) principle: any compiled Java code can run on any platform that supports Java without having to recompile it first. That’s possible thanks to the Java Runtime Environment (JRE), which runs on a Virtual Machine to provide it with that cross-platform capabilities. 

Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let application developers write once, run anywhere (WORA), meaning that compiled Java code can run on all platforms that support Java without the need for recompilation.