title: Error: java.lang.NumberFormatException: For input string: " 100"
body: <p>I am new to hadoop programming and while trying reduce side join i got error Error: java.lang.NumberFormatException: For input string: " 100". 
  I have checked the input file are Ok .</p>
  
  <p>My reducer Code is `    </p>
  
  <pre><code>public void reduce (IntWritable key , Iterable&lt;Text&gt; value , Context context) throws IOException , InterruptedException{
  
      // value : TRAN\t product name \t Amt and CUST \t custometr name
      String data = new String();
      int amount=0;
      String name =null;
      StringBuilder s = new StringBuilder();
      for (Text val : value){
  
          String[] line = val.toString().split("\t");
          if (line[0].equals(new String("TRANS").trim())){
              //data += line[1]+"\t";
              s.append(line[1]+"");
              amount+=Integer.parseInt(line[2]);
          }
          else if(line[0].equals(new String("CUST").trim())){
  
              name = line[1];
  
  
          }
  
          data= s.toString()+ Integer.toString(amount);
  context.write(new Text(name), new Text(data));
  </code></pre>
  
  <p>and my two mapper are :</p>
  
  <pre><code>package reduceSideJoin.reducejoin;
  
  public class transMapper extends Mapper&lt;LongWritable ,Text , IntWritable , Text &gt; {
  
  public void map(LongWritable key , Text value , Context context) throws IOException , InterruptedException{
  
      String[] line = value.toString().split(",");
      String data = "TRANS"+ "\t" + line[1]+"\t " + line[3];
      context.write(new IntWritable (Integer.parseInt(line[0])), new Text(data) );
  
      }
  
  }
  </code></pre>
  
  <p>and </p>
  
  <pre><code>package reduceSideJoin.reducejoin;
  
  public class userMapper extends Mapper&lt;LongWritable, Text, IntWritable, Text&gt; {
  public void map (LongWritable key, Text value , Context context) throws IOException , InterruptedException{
  
      String [] line = value.toString().split(",");
      String data = "CUST"+"\t"+line[1];
      context.write(new IntWritable (Integer.parseInt(line[0])), new Text(data));
  
      }
  
  } 
  </code></pre>
  
  <p>and my files are</p>
  
  <p>Transaction data </p>
  
  <pre><code>0001,crax,2,300
  0002,munch,1,10
  0003,lays,1,20
  0004,ship,1,200
  0005,barOne,3,400
  0002,crax,2,300
  0001,kurkure,3,100
  0003,milk,1,20
  0004,butter,2,300
  0005,meat,1,1220
  0002,color,1,230
  0003,dailrymilk,1,20
  </code></pre>
  
  <p>and customer data is </p>
  
  <pre><code>0001,Sunil Kumar , Mumbai,India
  0002,Vikas mandal, Haryana, India
  0003,Karan, JFK,France
  0004,manish,banglore,India
  0005,devesh,meerut,India
  </code></pre>
  
  <p>and i got error 16/05/30 00:23:00 INFO mapreduce.Job:  map 100% reduce 0%
  16/05/30 00:23:04 INFO mapreduce.Job: Task Id : attempt_1464547777880_0001_r_000000_0, Status : FAILED
  Error: java.lang.NumberFormatException: For input string: " 100"
      at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)</p>
  
  <p>Can someone help me to resolve this </p>
  
  <p>Thanks</p>