TINKERPOP-1444: Benchmark bytecode->Traversal creation and implement GremlinServer cache if necessary.

[okram]

https://issues.apache.org/jira/browse/TINKERPOP-1444

GremlinServer caching Map<Bytecode,Traversal> is only powerful (really powerful) when bindings are not involved (a solid 50x+ increase in speed). However, given that production systems will typically have bindings in their traversals, then such a cache doesn't help.

In its place, a update to JavaTranslator is provided that makes use of an internal static METHOD_CACHE so as to make reflection faster. The speed up is provided below:

Prior to method caching:
  Bytecode->JavaTranslator call    : 0.13305238800000002
After method caching:
  Bytecode->JavaTranslator call    : 0.054839154

CHANGELOG

* Added a static method cache to `JavaTranslator` to reduce the cost of Java reflection.

@spmallette --- if you think that a Map<Bytecode,Traversal> cache IS necessary for GremlinServer, then please VOTE -1 and we can collaborate on this branch to also include a bytecode-cache.

[spmallette]

I'm thinking that the cache hit count would be pretty low given the fact that bytecode contains parameters. since the hit count will be low, we'll just have the overhead of a cache without much value. it would be sweet if we could decouple the traversal from parameters so that a cache would be more effective, but i don't know what's involved with that offhand.

[spmallette]

VOTE +1

[dkuppitz]

All good, here's the missing

VOTE: +1