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ClassNotFoundException for Hbase

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ClassNotFoundException for Hbase

Hi,

I have created the code as below to write a record into hbase table of 1.1.2 version. I have included all the jars present in 1.1.2 hbase lib folder but while executing that I am getting the Error Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/hbase/HBaseConfiguration

Code

package com.hp;

import java.io.IOExceptionimport 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.Get;
import org.apache.hadoop.hbase.client.Put;
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;
import org.apache.hadoop.hbase.util.Bytes;
public class HbasePut 
{
public static void main(String[] args) throws IOException
{// You need a configuration object to tell the client where to connect.    
// When you create a HBaseConfiguration, it reads in whatever you've set    
// into your hbase-site.xml and in hbase-default.xml, as long as these can    
// be found on the CLASSPATH  
Configuration config = HBaseConfiguration.create();  
// Next you need a Connection to the cluster. Create one. When done with it,    
// close it (Should start a try/finally after this creation so it gets closed    
// for sure but leaving this out for readibility's sake).  
Connection connection = ConnectionFactory.createConnection(config); try 
{      
// This instantiates a Table object that connects you to      
// the "myLittleHBaseTable" table (TableName.valueOf turns String into TableName instance).      
// When done with it, close it (Should start a try/finally after this creation so it gets      
// closed for sure but leaving this out for readibility's sake).      
Table table = connection.getTable(TableName.valueOf("myLittleHBaseTable"));      
try 
{        
// To add to a row, use Put.  A Put constructor takes the name of the row        
// you want to insert into as a byte array.  In HBase, the Bytes class has        
// utility for converting all kinds of java types to byte arrays.  
//In the   below, we are converting the String "myLittleRow" into a byte array to
// use as a row key for our update. Once you have a Put instance, you can
// adorn it by setting the names of columns you want to update on the row,        
// the timestamp to use in your update, etc.If no timestamp, the server        
// applies current time to the edits.        
Put p = new Put(Bytes.toBytes("myLittleRow"));        
// To set the value you'd like to update in the row 'myLittleRow', specify
// the column family, column qualifier, and value of the table cell you'd 
// like to update.  The column family must already exist in your table
// schema.  The qualifier can be anything.  All must be specified as byte 
// arrays as hbase is all about byte arrays.  Lets pretend the table        
// 'myLittleHBaseTable' was created with a family 'myLittleFamily'.        
p.add(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("cf1"),Bytes.toBytes("SomeValue"));        
// Once you've adorned your Put instance with all the updates you want to
// make, to commit it do the following (The HTable#put method takes the        
// Put instance you've been building and pushes the changes you made into        // hbase)      
table.put(p);        
// Now, to retrieve the data we just wrote. The values that come back are        
// Result instances. Generally, a Result is an object that will package up        
// the hbase return into the form you find most palatable.        
/*Get g = new Get(Bytes.toBytes("myLittleRow"));        
Result r = table.get(g);        
byte [] value = r.getValue(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("cf1"));        
// If we convert the value bytes, we should get back 'Some Value', the    
// value we inserted at this location.        
String valueStr = Bytes.toString(value);        
System.out.println("GET: " + valueStr);        
// Sometimes, you won't know the row you're looking for. In this case, you        
// use a Scanner. This will give you cursor-like interface to the contents        
// of the table.  To set up a Scanner, do like you did above making a Put        
// and a Get, create a Scan.  Adorn it with column names, etc.        
Scan s = new Scan();        
s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("cf1"));        
ResultScanner scanner = table.getScanner(s);        
try 
{          
// Scanners return Result instances.          
// Now, for the actual iteration. One way is to use a while loop like so:          
for (Result rr = scanner.next(); rr != null; rr = scanner.next()) 
{             // print out the row we found and the columns we were looking for            
System.out.println("Found row: " + rr);          
}          
// The other approach is to use a foreach loop. Scanners are iterable!           // 
for (Result rr : scanner) 
{           //  
System.out.println("Found row: " + rr);           //
}        
} 
finally 
{          
// Make sure you close your scanners when you are done!          
// Thats why we have it inside a try/finally clause          
scanner.close();        
} 
*/        
// Close your table and cluster connection.      
} 
finally 
{
if (table != null) 
table.close();      
}    
} 
finally 
{      
connection.close();    
}  }

12 REPLIES 12
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Re: ClassNotFoundException for Hbase

Guru

you may try adding /etc/hadoop/conf to the classpath

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Re: ClassNotFoundException for Hbase

@krishna sampath

Did you tried exporting HADOOP_CLASSPATH variable in your env before running your java code?

Example:

export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/path/hbase<version>.jar

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Re: ClassNotFoundException for Hbase

is it in bashrc you are telling me to add or in ambari

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Re: ClassNotFoundException for Hbase

@krishna

you simply need to execute this command on shell prompt before you run java -cp

bash# export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/path/hbase<version>.jar

bash# export CLASSPATH=$CLASSPATH:$HADOOP_CLASSPATH

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Re: ClassNotFoundException for Hbase

@krishna

Please let us know if this issue got resolved after implementing suggested changes.

Thanks

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Re: ClassNotFoundException for Hbase

Contributor

If you've installed HBase client on your test environment, you could use this command to test your code:

export HBASE_CLASSPATH=$HBASE_CLASSPATH:<jar_compiled_using_your_code>

$HBASE_HOME/bin/hbase <package_name>.HbasePut

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Re: ClassNotFoundException for Hbase

where exactly we can add, I mean in the bashrc or in ambari(in ambari means where we can change)

Re: ClassNotFoundException for Hbase

Contributor

In the bash command line:

$ export HBASE_CLASSPATH=${HBASE_CLASSPATH}:<path_to_jar_compiled_using_your_code>

$ ${HBASE_HOME}/bin/hbase <package_name_of_your_class>.HbasePut

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Re: ClassNotFoundException for Hbase

how are you running the job with "java " or "hadoop jar"?