We are very paranoid with CHECKs in all Java entry points.
These CHECKs were added along with Java support.
At that point it wasn't clear what exactly to expect from JVM part
and if JVM part is correct or not. Thus CHECK paranoia.
These CHECKs never fired in practice, but we pay runtime cost
in every entry point all the time.
Replace CHECKs with DCHECKs.
Depends on D107069.