The Java(TM) 2 Runtime Environment is intended for software developers and vendors to redistribute with their applications.
The Java 2 Runtime Environment contains the Java virtual machine, runtime class libraries, and Java application launcher that are necessary to run programs written in the Java programming language.
Sun Java JRE is not a development environment and does not contain development tools such as compilers or debuggers. For development tools, see the Java 2 SDK, Standard Edition.
The J2SE Java Runtime Environment (JRE) allows end-users to run Java applications.