Program: 85700
Project: 85700
Buggy source:
private void SetupObservers(){
  tp.playlist.addObserver(new Playlist.PlaylistObserverAdapter(){
    @Override public void endUpdatePlaylist(){
      RefreshList(tp.playlist.GetList());
    }
  }
);
  tp.playlist.addObserver(new Playlist.PlaylistObserverAdapter(){
    @Override public void startUpdatePlaylist(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setVisibility(View.VISIBLE);
          rescanProgressBar.setIndeterminate(true);
          rescan.setVisibility(View.INVISIBLE);
        }
      }
);
    }
    @Override public void startRescan(    File mediaPath){
      final int[] numberOfTracks=new int[]{0};
      try {
        Process p=Runtime.getRuntime().exec(new String[]{"String_Node_Str","String_Node_Str",mediaPath.toString()});
        BufferedReader br=new BufferedReader(new InputStreamReader(p.getInputStream()));
        String line="String_Node_Str";
        while (line != null) {
          line=br.readLine();
          if (line != null && tp.playlist.isMP3.accept(null,line)) {
            numberOfTracks[0]=numberOfTracks[0] + 1;
          }
        }
      }
 catch (      IOException e) {
      }
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setIndeterminate(false);
          rescanProgressBar.setProgress(0);
          rescanProgressBar.setMax(numberOfTracks[0]);
        }
      }
);
    }
    @Override public void trackAdded(    Track track){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setProgress(rescanProgressBar.getProgress() + 1);
        }
      }
);
    }
    @Override public void endRescan(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setIndeterminate(true);
        }
      }
);
    }
    @Override public void endUpdatePlaylist(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setVisibility(View.GONE);
          rescan.setVisibility(View.VISIBLE);
          if (!tp.playlist.IsEmpty()) {
            SwitchToPlaylistSlide();
          }
 else {
            Toast.makeText(getApplicationContext(),"String_Node_Str",Toast.LENGTH_LONG).show();
          }
        }
      }
);
    }
  }
);
  tp.playlist.preferences.addObserver(new PreferencesObserver(){
    @Override public void changed(    Key key){
      if (key.equals(Keys.REPEAT)) {
        runOnUiThread(new Runnable(){
          @Override public void run(){
            boolean repeat=tp.playlist.preferences.GetRepeat();
            Toast.makeText(Player.this,repeat ? "String_Node_Str" : "String_Node_Str",Toast.LENGTH_SHORT).show();
            repeatButton.setImageDrawable(getResources().getDrawable(repeat ? R.drawable.repeat48_active : R.drawable.repeat48));
            repeatCheckBox.setChecked(repeat);
          }
        }
);
      }
 else       if (key.equals(Keys.SHUFFLE)) {
        runOnUiThread(new Runnable(){
          @Override public void run(){
            boolean shuffle=tp.playlist.preferences.GetShuffle();
            Toast.makeText(Player.this,shuffle ? "String_Node_Str" : "String_Node_Str",Toast.LENGTH_SHORT).show();
            shuffleButton.setImageDrawable(getResources().getDrawable(shuffle ? R.drawable.shuffle48_active : R.drawable.shuffle48));
            shuffleCheckBox.setChecked(shuffle);
          }
        }
);
      }
    }
  }
);
}

Fixed version (ground truth):
private void SetupObservers(){
  tp.playlist.addObserver(new Playlist.PlaylistObserverAdapter(){
    @Override public void endUpdatePlaylist(){
      RefreshList(tp.playlist.GetList());
    }
  }
);
  tp.playlist.addObserver(new Playlist.PlaylistObserverAdapter(){
    @Override public void startUpdatePlaylist(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setVisibility(View.VISIBLE);
          rescanProgressBar.setIndeterminate(true);
          rescan.setVisibility(View.INVISIBLE);
        }
      }
);
    }
    @Override public void startRescan(    File mediaPath){
      final int[] numberOfTracks=new int[]{0};
      try {
        Process p=Runtime.getRuntime().exec(new String[]{"String_Node_Str","String_Node_Str",mediaPath.toString()});
        BufferedReader br=new BufferedReader(new InputStreamReader(p.getInputStream()));
        String line="String_Node_Str";
        while (line != null) {
          line=br.readLine();
          if (line != null && tp.playlist.isMP3.accept(null,line)) {
            numberOfTracks[0]=numberOfTracks[0] + 1;
          }
        }
      }
 catch (      IOException e) {
      }
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setIndeterminate(false);
          rescanProgressBar.setProgress(0);
          rescanProgressBar.setMax(numberOfTracks[0]);
        }
      }
);
    }
    @Override public void trackAdded(    Track track){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setProgress(rescanProgressBar.getProgress() + 1);
        }
      }
);
    }
    @Override public void endRescan(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setIndeterminate(true);
        }
      }
);
    }
    @Override public void endUpdatePlaylist(){
      runOnUiThread(new Runnable(){
        @Override public void run(){
          rescanProgressBar.setVisibility(View.GONE);
          rescan.setVisibility(View.VISIBLE);
          if (!tp.playlist.IsEmpty()) {
            ResetFooterButtons();
            trackButton.setImageDrawable(getResources().getDrawable(R.drawable.track48_active));
            SwitchToPlaylistSlide();
          }
 else {
            Toast.makeText(getApplicationContext(),"String_Node_Str",Toast.LENGTH_LONG).show();
          }
        }
      }
);
    }
  }
);
  tp.playlist.preferences.addObserver(new PreferencesObserver(){
    @Override public void changed(    Key key){
      if (key.equals(Keys.REPEAT)) {
        runOnUiThread(new Runnable(){
          @Override public void run(){
            boolean repeat=tp.playlist.preferences.GetRepeat();
            Toast.makeText(Player.this,repeat ? "String_Node_Str" : "String_Node_Str",Toast.LENGTH_SHORT).show();
            repeatButton.setImageDrawable(getResources().getDrawable(repeat ? R.drawable.repeat48_active : R.drawable.repeat48));
            repeatCheckBox.setChecked(repeat);
          }
        }
);
      }
 else       if (key.equals(Keys.SHUFFLE)) {
        runOnUiThread(new Runnable(){
          @Override public void run(){
            boolean shuffle=tp.playlist.preferences.GetShuffle();
            Toast.makeText(Player.this,shuffle ? "String_Node_Str" : "String_Node_Str",Toast.LENGTH_SHORT).show();
            shuffleButton.setImageDrawable(getResources().getDrawable(shuffle ? R.drawable.shuffle48_active : R.drawable.shuffle48));
            shuffleCheckBox.setChecked(shuffle);
          }
        }
);
      }
    }
  }
);
}