which offer is better ?

I work in the USA. I got an offer from a company. They offer the similar salary as my current one, their java technology is newer than what I am using now. The working condition -- very crowded cubicle environment and faster pace. My current one -- stable job but java technology we use is old. Pay rate is close. Their job is not as stable as ours (they need to renew contract with their client every 5 months, for us every 3 years).

Shall I take the offer?

Neither is better. The answer depends on which of those criteria is most important to you.

You are best person to make that decision.

Here is something that may be of use to you --> http://java-success.blogspot.com/2007_10_01_archive.html

Having good work enviroment is important; also consider the duration of the Job and company's reputation in firing up employees in this bad market.