How to add JTree dynamically to a created JScrollPane?

MY Jtree component is created within a actionperformed function. But I've already created a Jscrollpane in the constructor and added it to the JFrame.

Now within the actionperformed function, I tried to add the dynamically created JTree开发者_StackOverflow社区 to the JScrollpane using

JScrollpaneobject.add(JtreeObject);
JScrollpaneobject.revalidate();

But I am unable to see the Jtree on the Jscrollpane.

---

direct variant of the same:

 scroll.setViewportView(jTree)

---

scroll.getViewport().add(jTree)