add test to show that BatchedExecutionStrategy doesn't work

across different paths

Alternative fix to dead lock challenge (graphql-java#1255)

* Added @OverRide as part of errorprone code health check

* Revert "Added @OverRide as part of errorprone code health check"

This reverts commit 38dfab1

* Brads attempt at graphql-java#1234

* Missed the test

fix master deployment

backport of graphql-java#1182

deploy branch builds

Merge pull request graphql-java#1097 from graphql-java/node-traverser

make NodeTraverser public and improves it with preOder/postOrder methods

9.0 release

Merge pull request graphql-java#989 from graphql-java/preparsed-docum…

…ent-assert

use graphql Assert

Throws a MissingRootTypeException instead of branching.

To DRY I removed branching in the `executeOperation` method and throws an error
whenever a query refers to a missing operation. This brings us a little closer to the
reference implementation https://github.com/graphql/graphql-js/blob/master/src/execution/execute.js#L419.

<T> javadoc fix up (graphql-java#815)

* More aggressive property look up

* <T> is for tea