[BUG] SDKClient execute() fails with NPE

[dbwiddis]

What is the bug?

SDKClient use of execute() implemented in #491 fails with NPE (actions is null) here:

TransportAction<Request, Response> transportAction = actions.get(action);

The root cause is that we incorrectly attempt to access an injected actions map:

// Used by client.execute
@SuppressWarnings("rawtypes")
@Inject
private Map<ActionType, TransportAction> actions;

However, the SDKClient was instantiated before injection so the map wasn't injected.

How can one reproduce the bug?

1. Run an extension and use the execute() method from SDKClient or SDKRestClient.
2. Observe REST error response that "actions" is null.

What is the expected behavior?

actions.get(action) returns an instance of a class implementing TransportAction.

Do you have any additional context?

The implementation was ported from NodeClient with this field populated by the initialize() method (and not by injection):

private Map<ActionType, TransportAction> actions;

This code from Node.java was not included in ExtensionsRunner shortly after injection completes, so porting it should fix this bug:

client.initialize(injector.getInstance(new Key<Map<ActionType, TransportAction>>() {}));

[dbwiddis]

A couple things were happening here:

• (This bug) Injection wasn't working because SDKClient was instantiated before the injection. This wasn't seen in the HelloWorld test case because of the initialization order was different.
• (Other bugs) The Injector was becoming unreachable due to GC and we were losing reference to all injected objects.