Java Runtime Environment (JRE) is a part of Java Development Kit(JDK), a set of programming tools made to develop java applications. In fact JRE provides a minimum environment to run java applications on your computer system. Java runtime environment includes Java Virtual Machine(JVM), Supporting Files and Core classes.
It’s important to make your java runtime environment updated so that you are updated with latest features and security fixes. JRE also installs some browser supporting files which helps us run java based browser applications on our web browsers. However when we download java JRE form it’s website, it often sends us an installer which requires internet connection to fully install java run-time environment. So we may need to download JRE offline standalone setup which will be carryable and requires no internet connection to install. For example MPowerPlayer requires JRE to run.
To download JRE offline Setup for your computer, just go to Java Download Page. And look for windows setups. At windows setup line find out the link for Offline. Then click there to download it.
The cross-platform java is available for Windows, Linux, Apple(Mac OS X)and Solaris. At the JRE Download page you will get all setup listed your Operating System. I think installers listed there for other operating systems should offline installer.