LinkageError at JavaMapping- UnsupportedClassVersionError in SAP PI 7.31

Hi Experts,

I am working on SAP PI 7.31 single stack and requirement is xml to xls conversion via Java mapping and I am using eclipse mars workbench due to some issues in NWDS. My JDK version is as per attached snippet:

But after compiling the attached code it is throwing error " LinkageError at JavaMapping.load(): Could not load class: "java.lang.UnsupportedClassVersionError:: Unsupported major.minor version"" 51.0 "

Can you please suggest.

Thanks,

Nithin.