Abstract method in Enums

Did you know that you can do that?

  private static enum DynamicProperty {

        cacheManagerName {
            @Override
            void applyChange(final PropertyChangeEvent evt, final RuntimeCfg config) {
                config.cacheManagerName = (String) evt.getNewValue();
            }
        },
        defaultCacheConfiguration {
            @Override
            void applyChange(final PropertyChangeEvent evt, final RuntimeCfg config) {
                LOG.debug("Default Cache Configuration has changed, previously created caches remain untouched");
            }
        };

        abstract void applyChange(PropertyChangeEvent evt, RuntimeCfg config);
}

I think it’s nice because it allows you to customize Enum’s behavior or perform other actions on use. 

Piece of code taken from EhCache Configuration (line 118 and further).