The test TestBiasedLockRevocationEvents.java assumes -XX:UseBiasedLocking is enabled. While this is generally true, it's not true when e.g. enabling ZGC. There's also work ongoing to look into disabling it by default (JDK-8231264). The test should supply -XX:+UseBiasedLocking on the run line to avoid making assumptions about if it's enabled by default or not.