This document discusses key features of the Java programming language that make it widely used. It explains that Java is write once run anywhere, as programs can run on any platform that has a Java Virtual Machine. It also describes Java as simple to write and debug, with features like automatic memory management, strong exception handling, and type checking. The document outlines the four main characteristics of object-oriented programming - inheritance, encapsulation, polymorphism, and dynamic binding - and how Java fully embraces these principles.