title: Not able to solve a run time exception in my project
body: <p><img src="https://i.stack.imgur.com/xslCB.png" alt="this is the error"></p>
  
  <p>I am developing a small project where i got a error which am unable to solve showing force close the application. Can any one help me</p>
  
  <p>and this is my screen3 code</p>
  
  <pre><code>public class screen3 extends ListActivity {
      /** Called when the activity is first created. */
      String[] names = new String[] { "India", "Malaysia"};
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.screen3);
          // Create an array of Strings, that will be put to our ListActivity
  
          // Use your own layout and point the adapter to the UI elements which
          // contains the label
          this.setListAdapter(new ArrayAdapter&lt;String&gt;(this, R.layout.screen3,
                  R.id.label, names));
          Button b4=(Button)findViewById(R.id.click);
          b4.setOnClickListener(new View.OnClickListener() {
  
              public void onClick(View v) {
                  // TODO Auto-generated method stub
                  Intent i2 =new Intent(screen3.this,screen4.class);
                  startActivity(i2);
              }
          });
      }
  
      @Override
      protected void onListItemClick(ListView l, View v, int position, long id) {
          super.onListItemClick(l, v, position, id);
          // Get the item that was clicked
          Object o = this.getListAdapter().getItem(position);
          String keyword = o.toString();
          if(keyword.equals("India"))
          {
              Intent i=new Intent(screen3.this,new21.class);
              startActivity(i);
  
          }
          Toast.makeText(this, "You selected: " + keyword, Toast.LENGTH_LONG)
                  .show();
  
      }
  
  }
  </code></pre>
  
  <p>and 
  the 26 line code is</p>
  
  <pre><code>public void onClick(View v) {
                  // TODO Auto-generated method stub
                  Intent i2 =new Intent(screen3.this,screen4.class);
                  startActivity(i2);
  </code></pre>
  
  <p>and i checked that it is fine</p>