public static Specification<Tag> hasPerfTest() {
		return (Specification<Tag>) (root, query, cb) -> {
			SetJoin<Object, Object> join = root.joinSet("perfTests");
			query.groupBy(root.get("id"));
			return join.get("id").isNotNull();
		};
	}
Get the {@link Specification} which checks if the tag has corresponding perfTests.

@return {@link Specification}
ngrinder-controller/src/main/java/org/ngrinder/perftest/repository/TagSpecification.java