How can programs written in Java not require the JRE?

Question

I had a fresh install and before installing Java was able to run NetBeans and OpenOffice. If these programs were written in Java, how is this possible? I know there exists some .class to .exe converters but I thought these are hacks (not suitable for large applications deployed worldwide). What is the common approach to deploying an application in Java without the JRE? Is there a standard, or most common way?

At first I thought it had to do with Jar files, but from what I red these require an existing Java installation to run.

Answer 1

All Java Applications Run on Top of a JRE. Even NetBeans and OpenOffice.

Most of the Deployable Java Applications have a JRE packaged with it. So that you may see it has no JRE but infact there is one with it and the Application will run on top of it.