JRE and JVM interview Question ....

[sunil choudhary]

I was asked the difference between the two...
I said..that JRE can stand alone run the java applications in case of Resource shortages.. and can function without JVM also..

Can some one add some more things to this aspect....
Please
.....
Sunil

[rani bedi]

The JRE (Java Runtime Environment) is the equivalent of a JVM but for running applications outside of a browser (like from the DOS prompt).
When you run an applet or servlet it is running in a JVM (Java Virtual Machine). It is actually a set of specifications that Sun gives to the makers of browsers to follow when creating their JVMs.

[sunil choudhary]

so parmeet
Does that mean that when I compile a program from Dos prompt then I am just using the JRE and not JVM ..are they really separate or just a subset...
thanks for your reply..
Sunil Choudhary

[Scott Pedigo]

The JRE is a product from Sun which has a JVM in it.
A JVM is an implementation of Sun's specifications for something - could be hardware, could be software, could be a browser - which interprets the Java byte code, executing it on a platform.

[sunil choudhary]

Thanks Scott
I got the point...
Sunil

[Cindy Glass]

Actually the SDK has the JRE in it.
If you compile from the prompt you are using the SDK. If you run from the prompt you are using the JRE.

[sunil choudhary]

Thanks Cindy
Sunil Choudhary