How do i recalculate preferred size of a JComponent?

Question

I know the fact that when I create an instance of a JComponent, it has it's own preferred size. Now let's suppose that I setPreferredSize that JComponent manually with a dimension of 0 x 0. And i want that Component to "reset" its own preferredSize. How do I do that?

Answer 1

1) Setting preferred size to null should reset the component back to getting its preferred size calculated as if it was never set.

component.setPreferredSize(null);

This might not do what you want, depending on how you signal that the layout should be redone - but at least it is technically the answer to your question.

2) It is generally advised to not use setPreferredSize, see this post