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By default, any -XX: options that you specify on the command line are ignored if they are not recognized, which prevents an application failing to start. However, if you want to determine whether any of your -XX: options are unrecognized, you can turn off the behavior with this option. You might want to do this, for example, if you are switching to Eclipse OpenJ9™ from an alternative VM implementation where you are using -XX: options to tune the runtime environment.


Setting Effect Default
-XX:+IgnoreUnrecognizedXXColonOptions Enable yes
-XX:-IgnoreUnrecognizedXXColonOptions Disable

When you specify -XX:-IgnoreUnrecognizedXXColonOptions, if you also specify a -XX: option that is not recognized, that option is reported and the VM does not start. For example:

JVMJ9VM007E Command-line option unrecognised: -XX:InvalidOption
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.