java Component's getSize() returning negative values

Question

I have a funny situation in which intermittently I get negative values from calling a JLabel's method getSize(). I want to resize a JLabel to grab the maximum space possible but very often I get it upside down like in this question. It seems that an instant after acquiring that negative value the right one is available. I am almost sure that this is a thread race problem caused by my bad GUI/logic thread architecture, however, I noticed that if I remove this workaround that I made to the parent JPanel, the problem disappears.

I already tried adding a synchronized block while doing the value assignment, I did jlabel.verify() before but nothing helped. Unfortunately, I really need to keep the workaround I mentioned.

I would appreciate any guidance to solve this problem, thanks in advance.

Here is a screenshot:

Answer 1

The only way something like this can happen is if another process is changing jlabel between the time componentWidth variable was assigned and the time you are reading its value. A likely scenario is that jlabel's initialization is happening in a background thread, and was not complete when you assigned the componentWidth variable.