Adversaries might be able to forge data which can be abused for DoS attacks.
These classes are already writing a replacement JDK object during serialization
for a long time, so this change should not cause any issues.
The most interesting optimization is to replace ArrayDeque with a manual linked list that reuses the nodes 'parent' field. These optimizations save about 20%.
Compared to LinkedTreeMap, this is slower for small (size=5) maps: 124% slower to get() and 33% slower to create and populate. It's a win for large (size=500) maps: 46% faster to get() but 8% slower to create and populate. And it's a big win for very large (size=50,000) maps: 81% faster to get() and 46% faster to create and populate.
http://microbenchmarks.appspot.com/run/limpbizkit@gmail.com/com.google.common.collect.MapBenchmark
I'm going to follow this up with some simple optimizations: caching local fields and simplifying access. That should narrow the performance gap.
Not yet adopted in our code.
Known critical bugs:
- throws ClassCastException when get() is called with a non-comparable key
- throws NullPointerException on get(null)
