Question : ORA-07445

I'm getting this error. Any ideas?
ORA-07445: exception encountered: core dump [pfr_v3_tab_handler()+656] [SIGSEGV] [Address not mapped to object] [0x40403042BF3E6A47] [] [] ORA-00600: internal error code, arguments: [19708], [], [], [], [], [], [], []

Answer : ORA-07445

Iterator:

1:	Iterator<Map.Entry<Integer, ColumnnData>> it = columnValues.entrySet().iterator();