Please review this changeset including: 1) change `JfrJavaSupport::get_field_global_ref()` to return a `bool` so that in `install_chunk_monitor()` in `jfrChunkRotation.cpp`, it checks the return status before doing `result.get_jobject()`. 2) add an `assert` in `JfrDCmd::print_help()` to make sure the `result` is of `T_OBJECT` type. Passed tiers 1 - 4 testing. ------------- Commit messages: - 8297877: jfr functions should check JavaValue result before use Changes: https://git.openjdk.org/jdk/pull/11934/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11934&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8297877 Stats: 10 lines in 4 files changed: 5 ins; 0 del; 5 mod Patch: https://git.openjdk.org/jdk/pull/11934.diff Fetch: git fetch https://git.openjdk.org/jdk pull/11934/head:pull/11934 PR: https://git.openjdk.org/jdk/pull/11934