As stated in XXX
https://sourceforge.net/tracker/index.php?func=detail&aid=1799560&group_id=131157&atid=721510
the REST class relies on a non-thread safe xml dom parser by default.
The patch puts the parser in a thread-local, which solves the problem.
Patch based on 1.22 of REST.java
http://flickrj.cvs.sourceforge.net/\*checkout*/flickrj/api/src/com/aetrion/flickr/REST.java?revision=1.22
Patch file for rev 1.22 of REST.java
REST.java 122 fixed
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Here's a drop-in replacement for 1.22 which is used in release 1.0
File Added: REST122b.java
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Why bother caching the parser at all? Does it make a measurable speed difference? Keep it simple unless you know it makes a difference.