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

Sometimes I had troubles with the Eclipse preferences, so if nothing seems to help anymore I try the following.

Switch to the Navigator view, open your project and the .settings folder. Check for the following files and check/update the following settings (depending on the project type there might be different files). I just opened a maven web project.

file org.eclipse.jdt.core.prefs:

org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.6
org.eclipse.jdt.core.compiler.compliance=1.6
org.eclipse.jdt.core.compiler.source=1.6

file org.eclipse.wst.common.project.facet.core.xml:

   
   ...
 

file .classpath (in app root, not .settings directory)

Basicly you can search for 1.7 and 7.0 in the enclosing project, to check/update the settings.