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As I see the main reason to use this switch is to be able to use Java Flight Recorder.

Any references that this switch is a paid 'feature'? And what other options are behind it?

Other than the name of the option? and the fact that this rather clearly spelled out in the OracleJDK binary license text? http://www.oracle.com/technetwork/java/javase/terms/license/... and otherwise documented at http://www.oracle.com/technetwork/java/javase/terms/products...