title: Testing java HBase connection
body: <p>I am trying to use the HBase Java APIs to write data into HBase. I installed Hadoop/HBase through Ambari.</p>
  
  <p>Here is how the configuration is currently set up:</p>
  
  <pre><code>final Configuration CONFIGURATION = HBaseConfiguration.create();
  final HBaseAdmin HBASE_ADMIN;
  
  HBASE_ADMIN = new HBaseAdmin(CONFIGURATION)
  </code></pre>
  
  <p>When I try to write to HBase, I check to make sure that the table exists    </p>
  
  <pre><code>!HBASE_ADMIN.tableExists(tableName)
  </code></pre>
  
  <p>If not, create a new one. However, it appears that when attempting to check if the table exists exceptions are being thrown.</p>
  
  <p>I'm wondering if I'm not correctly connected to HBase...is there any good way to verify that the configuration is correct and that I am connecting to HBase?  The exception I'm getting is below.</p>
  
  <p>Thanks.</p>
  
  <hr>
  
  <pre><code>java.lang.RuntimeException: java.lang.NullPointerException
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:209)
    at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:288)
    at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:268)
    at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:140)
    at org.apache.hadoop.hbase.client.ClientScanner.&lt;init&gt;(ClientScanner.java:135)
    at org.apache.hadoop.hbase.catalog.MetaReader.fullScan(MetaReader.java:597)
    at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:802)
    at org.apache.hadoop.hbase.catalog.MetaReader.tableExists(MetaReader.java:359)
    at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:287)
    at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:301)
    at com.business.project.hbase.HBaseMessageWriter.getTable(HBaseMessageWriter.java:40)
    at com.business.project.hbase.HBaseMessageWriter.write(HBaseMessageWriter.java:59)
    at com.business.project.hbase.HBaseMessageWriter.write(HBaseMessageWriter.java:54)
    at com.business.project.storm.bolt.package.exampleBolt.execute(exampleBolt.java:19)
    at backtype.storm.daemon.executor$fn__5697$tuple_action_fn__5699.invoke(executor.clj:659)
    at backtype.storm.daemon.executor$mk_task_receiver$fn__5620.invoke(executor.clj:415)
    at backtype.storm.disruptor$clojure_handler$reify__1741.onEvent(disruptor.clj:58)
    at backtype.storm.utils.DisruptorQueue.consumeBatchToCursor(DisruptorQueue.java:125)
    at backtype.storm.utils.DisruptorQueue.consumeBatchWhenAvailable(DisruptorQueue.java:99)
    at backtype.storm.disruptor$consume_batch_when_available.invoke(disruptor.clj:80)
    at backtype.storm.daemon.executor$fn__5697$fn__5710$fn__5761.invoke(executor.clj:794)
    at backtype.storm.util$async_loop$fn__452.invoke(util.clj:465)
    at clojure.lang.AFn.run(AFn.java:24)
    at java.lang.Thread.run(Thread.java:745)
  Caused by: java.lang.NullPointerException
    at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.getMetaReplicaNodes(ZooKeeperWatcher.java:269)
    at org.apache.hadoop.hbase.zookeeper.MetaRegionTracker.blockUntilAvailable(MetaRegionTracker.java:241)
    at org.apache.hadoop.hbase.client.ZooKeeperRegistry.getMetaRegionLocation(ZooKeeperRegistry.java:62)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateMeta(ConnectionManager.java:1203)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1164)
    at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:294)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:130)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:55)
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:201)
  </code></pre>