Hbase ResultScanner throws a Null Pointer Exception

Question

I wrote a hbase java client as follows.

package hbase;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;

public class Sample {


    public static void main(String[] args) throws IOException{
        // Instantiating Configuration class
           System.out.println("Trying to connect...");

           Configuration conf = HBaseConfiguration.create();
           System.out.println("HBase is running!");

           Connection conn = ConnectionFactory.createConnection(conf);
           Table  table = conn.getTable(TableName.valueOf("demo"));
           Scan scan1 = new Scan();

           ResultScanner scanner1 = table.getScanner(scan1);

           for(Result res: scanner1){
               System.out.print(res);
           }

           System.out.println("Table created Successfully...");

    }
}

Following is the output

Trying to connect...
HBase is running!
log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
2017-03-22 18:24:32.271 java[29447:3527085] Unable to load realm mapping info from SCDynamicStore
Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: java.lang.NullPointerException
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:208)
    at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:320)
    at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:295)
    at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:160)
    at org.apache.hadoop.hbase.client.ClientScanner.<init>(ClientScanner.java:155)
    at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:821)
    at hbase.Sample.main(Sample.java:29)
Caused by: java.lang.RuntimeException: java.lang.NullPointerException
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:208)
    at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.loadCache(ClientSmallReversedScanner.java:211)
    at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.next(ClientSmallReversedScanner.java:185)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegionInMeta(ConnectionManager.java:1249)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1155)
    at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:300)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:151)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:59)
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200)
    ... 6 more
Caused by: java.lang.NullPointerException
    at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.getMetaReplicaNodes(ZooKeeperWatcher.java:395)
    at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.blockUntilAvailable(MetaTableLocator.java:553)
    at org.apache.hadoop.hbase.client.ZooKeeperRegistry.getMetaRegionLocation(ZooKeeperRegistry.java:61)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateMeta(ConnectionManager.java:1185)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1152)
    at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:300)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:151)
    at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:59)
    at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200)
    ... 14 more

I have already created a table in hbase using the hbase shell. I am running HDP 2.5 and my code from eclipse on OS X EI Captian.
I copied the hbase-site.xml in my local path.

Your issue seems similar to the outlined on question: http://stackoverflow.com/questions/7134723/hadoop-on-osx-unable-to-load-realm-info-from-scdynamicstore — cjackson, Mar 23 '17 at 12:41

score 0 · Answer 1 · answered Mar 23 '17 at 16:36

As per your code, I can understand that you are creating the HbaseConfiguration without adding any configuration information in your class. So I assume you would have added the hbase-site.xml in the classpath. If not, you have to do add it or set the zookeeper znode and quorum details in your class like below.

       Configuration conf = HBaseConfiguration.create();
       conf.set("zookeeper.znode.parent", <hbase znode>) 
       conf.set("hbase.zookeeper.quorum", <quorum ip>);
       conf.set("hbase.zookeeper.property.clientPort", <port>);

       Connection conn = ConnectionFactory.createConnection(conf);

Hbase ResultScanner throws a Null Pointer Exception

1 Answers1