Shell parent= JavaPlugin.getActiveWorkbenchShell();

OpenTypeSelectionDialog dialog= new OpenTypeSelectionDialog(parent, false,

PlatformUI.getWorkbench().getProgressService(),SearchEngine.createWorkspaceScope(), IJavaSearchConstants.TYPE);

dialog.setTitle(ActionMessages.OpenTypeInHierarchyAction_dialogTitle);

dialog.setMessage(ActionMessages.OpenTypeInHierarchyAction_dialogMessage);

int result= dialog.open();

if (result != IDialogConstants.OK_ID)

   return;

Object[] types= dialog.getResult();

if (types != null && types.length > 0) {

   IType type= (IType)types[0];

}