title: java.io.NotSerializableException even if i implement "Serializable"
body: <p>I have a little problem:
  I wanted to test serialization on android (using eclipse) and found an example how to do it.
  I know I need to implement "Serializable" in the class I want to serialize, I already did that and always get a java.io.NotSerializableException exception. Here's the code:</p>
  
  <pre><code>public void Button(View view) throws IOException, ClassNotFoundException {
  ser test = new ser();
      test.x = 204;
      test.y = 2843;
      test.speed = 12;
      test.direction = 1343;
      test.a = 493;
      test.b = 2323;
      test.c = 29489;
      test.d = 394;
  
      byte[] arr = serialize(test);
  
      ser res = (ser) deserialize(arr);
  }
  
  
  public static byte[] serialize(Object o) { 
      ByteArrayOutputStream bos = new ByteArrayOutputStream();  
      try {   
          ObjectOutput out = new ObjectOutputStream(bos);      
          out.writeObject(o);                                       //This is where the Exception occurs
          out.close();     
          // Get the bytes of the serialized object    
          byte[] buf = bos.toByteArray();   
          return buf;    
      } catch(IOException ioe) { 
          Log.e("serializeObject", "error", ioe);           //"ioe" says java.io.NotSerializableException exception
          return null; 
      }  
  
  }
  
  
  public static Object deserialize(byte[] b) {  
          try {    
              ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(b));    
              Object object = in.readObject();    
              in.close();  
              return object;  
          } catch(ClassNotFoundException cnfe) {   
              Log.e("deserializeObject", "class not found error", cnfe);   
              return null;  
          } catch(IOException ioe) {  
              Log.e("deserializeObject", "io error", ioe);    
              return null; 
          } 
      } 
  
  class ser implements Serializable {
      float x, y, speed, direction, a, b, c, d;
  }
  </code></pre>
  
  <p>I hope you can help me, I don't know what I did wrong...</p>
  
  <p>Edit: my imports are:</p>
  
  <pre><code>import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutput;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  
  import android.app.Activity;
  import android.os.Bundle;
  import android.util.Log;
  import android.view.View;
  import android.widget.TextView;
  </code></pre>