Major Description
It appears that Apache Curator does not execute the sync callback on the supplied Executor in at least one case.
This issue described is currently (2015-10-14) present in master
Sample code outline:
BackgroundCallback myCallback = ...;
Executor myExecutor = ...;
String myZkPath = ...;
CuratorFramework myCurator = ...;
curator.sync()
.inBackground(myCallback, myExecutor)
.forPath(myZkPath);
This should execute myCallback on the myExecutor executor, it does not and instead executes myCallback on what is presumeably a ZooKeeper thread.
Looking at the org.apache.curator.framework.imps.SyncBuilderImpl code we have
public Pathable inBackground(BackgroundCallback callback, Executor executor) { backgrounding = new Backgrounding(callback, executor); return this; }
However the only matching constructor in org.apache.curator.framework.imps.Backgrounding is Backgrounding(BackgroundCallback callback, Object context)
It seems that SyncBuilderImpl#inBackground(BackgroundCallback,Executor) should be using the following Backgrounding constructor Backgrounding(CuratorFrameworkImpl, BackgroundCallback, Executor)
A workaround looks to be using the following method and passing a null context object:
public Pathable inBackground(BackgroundCallback callback, Object context, Executor executor)
A very quick skim suggests that it is only SyncBuilderImpl that has the issue the other org.apache.curator.framework.imps.*BuilderImpl classes seem to be fine.