Upgrading Database To 12.2 Makes Java Objects Invalid And Recompilation Fails With ORA-00600 , , 
Last updated on MAY 07, 2018
Applies to:Oracle Database - Enterprise Edition - Version 126.96.36.199 and later
Information in this document applies to any platform.
After upgraded the database to 12.2 from some lower database versions like 12.1 or 11.2. Some of the Java Classes become invalid and the recompilation of this Java sources leads to the ORA-00600:, ,  error.
1.The problem has been demonstrated with following examples
Create following Java sources in 11.2 or 12.1 database (i.e < 12.2)
Upgraded the database to 12.2 from 12.1 or 188.8.131.52
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