For my JSP charting tag library (cewolf), I'm trying to figure out if the ImageIO API is thread-safe. Some suggest yes, but the ImageIO Guide specifically states that thread-safety is a non-goal. ImageIO.write in particular looks like it might cache and reuse ImageWriter objects, and thus not be thread-safe. Has anyone confirmed that one way or the other?
Even if ImageIO.write were not thread-safe, would creating ImageWriter objects some other way (allocating new ones for each request, assuming that's possible) be thread-safe?
The javadocs don't talk about thread-safety at all. Thanks in advance for any pointers.