Is there any way to find out if the class has been compiled for java6?

Question

How should I do to find out if the java class has been compiled for use in java 6 vm?

Is there an easy way?

Answer 1

The specification of the class file format . The WP article on this subject includes the current set of version number constants.

Answer 2

On unix,

$ javap -classpath <classpath> -verbose foo.Bar \
  | grep -q 'major version: 50' && echo yep || echo nope

thanks @matt b. A.

Answer 3

Using java decompiler