From the JLS:
15.9.5
An anonymous class is never abstract (�8.1.1.1). An anonymous class is always an inner class (�8.1.2); it is never static (�8.1.1, �8.5.2). An anonymous class is
always implicitly final (�8.1.1.2).
8.1.2
Inner classes may not declare static members, unless they are compile-time constant fields (�15.28).
So it is ok to have static final variables.