Add notes about performance
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@515 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/java/README b/java/README
index 87d3181..ebe564e 100644
--- a/java/README
+++ b/java/README
@@ -18,6 +18,25 @@
builds .class files for both the front end and example code.
+Performance Pitfalls
+--------------------
+
+The TurboJPEG Java front end defines several convenience methods which can
+allocate image buffers or instantiate classes to hold the result of compress,
+decompress, or transform operations. However, if you use these methods, then
+be mindful of the amount of new data you are creating on the heap. It may be
+necessary to manually invoke the garbage collector to prevent heap exhaustion
+or to prevent performance degradation. Background garbage collection can kill
+performance, particularly in a multi-threaded environment (Java pauses all
+threads when the GC runs.)
+
+The Java front end always gives you the option of pre-allocating your own
+source and destination buffers, which allows you to re-use these buffers for
+compressing/decompressing multiple images. If the image sequence you are
+compressing or decompressing consists of images of the same size, then
+pre-allocating the buffers is recommended.
+
+
Note for OS X users
-------------------