Target JRE in Eclipse

Question

How should I change Target JRE in Eclipse. I was earlier using jdk1.7, now I want to use JDK 1.6. But while running my java program I am getting Unsupported Class Version Er

Answer 1

If the project has been already started with JDK 1.6, you have to change also the project level settings, so :

Project ---> Properties ---> Java Compiler : set compliance level and Source compatibility to 1.7

Project ---> Properties ---> Java Build Path ---> Libraries ---> and change the JRE system library to 1.7