How do I invoke a java code in a different java environment?

I have the below version in Matlab.

version -java

ans = Java 1.6.0_12-b04 with Sun Microsystems Inc. Java HotSpot™ Client VM mixed mode

However, getenv('MATLAB_JAVA') is not returning me empty result. >> getenv('MATLAB_JAVA')

ans =

     ''

Couple of questions.

1. How do I run a java program in a different java version(1.7.0_60), other than the current java version(1.6.0_12-b04)? Note, I don't want to change the java path of matlab permanently to 1.7.0_60 .

2. From where is the current java(1.6.0_12-b04) picked by matlab?

Thanks a lot!

Sunil Kumar