public class MyLabelProvider extends ColumnLabelProvider  {

    @Override
  public Image getImage(Object element) {
      retrun null;
  }

  @Override
  public String getText(Object element) {
     return "some text";
  }
  
 

  /* (non-Javadoc)
   * @see org.eclipse.jface.viewers.CellLabelProvider#update(org.eclipse.jface.viewers.ViewerCell)
   */
  @Override
  public void update(ViewerCell cell) {
    // TODO Auto-generated method stub
    cell.setText(cell.getElement().toString());
  }
  
  @Override
  public String getToolTipText(Object element) {
    return "Tooltip (" + "test "+ ")";
  }

  @Override
  public Point getToolTipShift(Object object) {
    return new Point(5, 5);
  }

  @Override
  public int getToolTipDisplayDelayTime(Object object) {
    return 0;
  }

  @Override
  public int getToolTipTimeDisplayed(Object object) {
    return 5000;
  }



}

TreeViewer viewer = new TreeViewer(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);

viewer.setContentProvider(new TreeNodeContentProvider());
ColumnViewerToolTipSupport.enableFor(viewer,ToolTip.NO_RECREATE);

viewer.setLabelProvider(new MyLabelProvider ());

viewer.setInput(someInput());