Java runtime environment

Java Runtime Environment (JRE) is included in JDK. It is one of the main part of a JDK to run java applications. It is a minimum requirement to run any java application.

Java Runtime Environment consists of Java Virtual Machine (JVM), various core classes, libraries and various other components to run java programs and applets. JRE plug-in is installed in every browser to run java applets and to deploy Java Web Start.

Java Web Start is used to deploy individual application over the network.

Java Runtime Environment is a sub-set of JDK and it is can also be downloaded separately. JRE is required on all operating systems to run java applications. It is also present on mobile devices which are capable of running java applications.

Java Runtime Environment is the very basic requirement to run java programs. It loads and runs java applications with the use of JVM.

When a java file is complied it generates a byte code file i.e. “.class” file. The byte code file is platform independent but the Java Runtime Environment is platform dependent. It means if you need to run java programs on Linux, you need a JRE for Linux. JRE is present for most of the operating system.

Hence java programs are platform independent but Java Runtime Environment is platform dependent means different platform have different JRE.