The original JMX 1.0 spec contained an inconsistency regarding the
currencyTimeLimit field in Model MBean descriptors. The PDF spec said
that the value 0 meant that the value was not cached, while the value
-1 meant that it was cached forever. The Javadoc said the opposite.
The RI agreed with the PDF.

In JMX 1.1, the RI was "fixed" to agree with the Javadoc. The
inconsistency with the PDF was apparently not noticed at this time.

In JMX 1.2, the PDF was "fixed" to agree with the Javadoc and RI.

This has led to a hopeless situation where the JMX 1.0 RI and most if
not all independent implementations of JMX have the "0 means not
cached" semantics (which are also the most logical semantics), while
the JMX 1.2 RI and spec have the "-1 means not cached" semantics.