HBASE-1999 When HTable goes away, close zk session in shutdown hook or something...

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@883189 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -114,6 +114,8 @@ Release 0.21.0 - Unreleased
    HBASE-1979  MurmurHash does not yield the same results as the reference C++
                implementation when size % 4 >= 2 (Olivier Gillet via Andrew
                Purtell)
+   HBASE-1999  When HTable goes away, close zk session in shutdown hook or
+               something...
 
   IMPROVEMENTS
    HBASE-1760  Cleanup TODOs in HTable

src/java/org/apache/hadoop/hbase/client/HConnectionManager.java

@@ -68,6 +68,16 @@ public class HConnectionManager implements HConstants {
   private static final Delete [] DELETE_ARRAY_TYPE = new Delete[0];
   private static final Put [] PUT_ARRAY_TYPE = new Put[0];
 
+  // Register a shutdown hook, one that cleans up RPC and closes zk sessions.
+  static {
+    Runtime.getRuntime().addShutdownHook(new Thread("HCM.shutdownHook") {
+      @Override
+      public void run() {
+        HConnectionManager.deleteAllConnections(true);
+      }
+    });
+  }
+
   /*
    * Not instantiable.
    */