Andy eval20 - #138

…eException (#131)

* 1. replace JdiObjectProxy with StackFrameProxy, because only stackframe uses it .

* 1. add a missing import.

* rename a variable

* fix compilation error after merge

* 1. add lock to prevent concurrent stackframe access
2. redefine the StackFrameProxy to only have thread and depth since the stackframe instance may be out of date
3. add stackframe provider and add logic to update stackframe during evaluation.

* add stackframe provider and add logic to update stackframe during evaluation.

* fix for a better flow

* fix for a better flow

* revert minor changes which is not needed.

* remove useless lines.

* clean evaluation inner states when the thread is to be continued.

* clean evaluation inner states when the thread is to be continued.

* lock on acquireEvaluationLock

* remove the duplicate expr check

* revert unneeded change

* refine if-else flow.

* redefine the lock

* change another method to override indicating sf is updated.

* rename some classes suggested by reviewer

* 1. refact variableProxy to contain thread reference,
2. stackframes/varaible/setVariable/evaluate will first gain the thread lock on stack frame manager.

* some minor changes of spaces and javadoc.

* convert to supplyAsync with try logic to handle lock

* Andy eval20 (#138)

* Redefine HCR event. (#133)

* Sequentially process debug requests (#135)

* bump version to 0.5.0 (#136)

* Redefine HCR event.

* bump version to 0.5.0

Signed-off-by: Jinbo Wang <[email protected]>

* don't use lock

* don't use lock

* don't use lock

* Minor changes: indentation, rename code -> expression