Can I safely upgrade JAVA?

Hi, ALL,
Here is my question:

I have IBM ThinkPad that was produced before Jan 1 2005.
It still has all IBM software which includes "IBM 32-bit Runtime Environment for Java 2 v.1.4.2".
Trying to find an update from IBM I found that this is the latest recommended update for that laptop.

Is it possible to update the Java version to the latest version from Sun, since the one it has is way too old?

Thank you.

 

You can safely install more than one version of Java on a pc, just as you can install more than one version of .net framework.

 

That is correct statement. However, I'm worried that IBM does not produce JAVA update, and therefore I'm worried about breaking something, that used to work with IBM JAVA and won't with latest Sun JAVA update.

Hence the question: can I assume that IBM JRE and Sun JRE are the same and perform the update without any problems?

Thank you.

 

OK, thx.
This is what I thought, but wanted to confirm.