com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`exercisegenerator`.`exercise`, CONSTRAINT `exercise_exam_id_fk` FOREIGN KEY (`examid`) REFERENCES `exam` (`id`) ON DELETE CASCADE ON UPDATE CASCADE)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_101]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_101]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_101]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_101]