def x=2def y=3if(x == y){	log.info "equal"}else{	log.info "not equal"   // print out not equal}TestService s1 =  new TestService()TestService s2 =  new TestService()log.info s1.is(s2)   // falses1=s2log.info s1.is(s2)   // trueclass TestService{	}

Run result:

Tue Oct 06 21:04:38 CST 2015:INFO:not equalTue Oct 06 21:04:38 CST 2015:INFO:falseTue Oct 06 21:04:38 CST 2015:INFO:true