The Java Runtime Environment (JRE) is intended for software developers.
Editor: The Java(TM) Platform, Standard Edition Runtime Environment (JRE) is intended for software developers and vendors to redistribute with their applications.
The Java SE Runtime Environment is the minimum standard Java computing environment for running applications written in the Java programming language. It contains the Java virtual machine, Java core classes, and supporting files. It does not contain any of the development tools (such as appletviewer or javac) or classes that pertain only to a development environment.
The Java SE 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. It is not a development environment and does not contain development tools such as compilers or debuggers. For development tools, see the Java SE Development Kit (JDK(TM)). you can free download Java Runtime Environment 1.2 now.