Java Runtime Environment - Runtime Environment created by Sun Microsystems that allows to run and use applications written in the programming language Java. It consists of a virtual machine - Java Virtual Machine and Java-library classes. Written in the Java language a lot of programs and games, especially those for whom mobility is important. Some Web pages are also using Java. One of the advantages of Java is its cross-platform, that is, an application written in this language can be used on different operating systems where you installed Java Runtime Environment.