Error says 'configure to use a jdk' though eclipse uses its own compiler. What could be the reason for it?

Question

The markers window shows this error -

Your project must be configured to use a JDK in order to use JSPs.

Eclipse by default uses it's own JDK. What could be the problem then ?

Along, I am using Google App Engine .

Marker Window -

Answer 1

Looks like eclipse is configured to use JRE not JDK

verify & change

windows > preference > java > installed JRE > choose JDK here

Eclipse when started using java from JRE it doesn't still respect this setting, specifying JDK;s java for eclipse fixed it

-vm
/home/non-admin/jdk1.7.0_02/bin/java 

Answer 2

Go into your 'Project Properties', then go to 'Java Build Path', then to 'Libraries' tab, there you will see 'JRE System Library'. If that doesn't points to the JDK you are using, then 'Edit' it to the correct one.