I was using Single Table mapping @Inheritance(strategy = InheritanceType.SINGLE_TABLE) It was working fine.
After I changed it to Table per class, @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
I got the following exception when trying to loading data:
Exception in thread "HSQLDB Connection @170c7a3" java.lang.ClassCastException: java.lang.Integer at org.hsqldb.rowio.RowOutputBase.writeData(Unknown Source) at org.hsqldb.Result.write(Unknown Source) at org.hsqldb.Result.write(Unknown Source) at org.hsqldb.ServerConnection.run(Unknown Source) at java.lang.Thread.run(Thread.java:595)
I tried both MySQL and HyperSonic. Any ideas? any help is appreciated.