THRIFT-4233: Make THsHaServer.invoker available (get method only) in inherited classes
Client: hs

This closes #1366
diff --git a/lib/java/src/org/apache/thrift/server/THsHaServer.java b/lib/java/src/org/apache/thrift/server/THsHaServer.java
index 3b8fb35..4c5d7b5 100644
--- a/lib/java/src/org/apache/thrift/server/THsHaServer.java
+++ b/lib/java/src/org/apache/thrift/server/THsHaServer.java
@@ -155,6 +155,9 @@
     return invoker;
   }
 
+  protected ExecutorService getInvoker() {
+    return invoker;
+  }
 
   protected void gracefullyShutdownInvokerPool() {
     // try to gracefully shut down the executor service