FlowLayout.layoutContainer() does not protect itself against components being removed while it's iterating through its target's sub-components. An ArrayIndexOutOfBoundsException is raised.

To reproduce:

1) Visit http://wombat.eng/~brie/kona/thread/basher/BashTest.html
2) Click "Start" about 20 times in very quick succession.
3) Under normal or un-stressed circumstances, the status bar would return to "No bashing" after the death of every thread. However, if a thread dies due to this bug, it wouldn't decrement the count (which is handled after the validate()). Also, System.err displays:

java.lang.ArrayIndexOutOfBoundsException: No such child: 8
        at java.awt.Container.getComponent(Container.java:72)
        at java.awt.FlowLayout.moveComponents(FlowLayout.java:172)
        at java.awt.FlowLayout.layoutContainer(FlowLayout.java:215)
        at java.awt.Container.layout(Container.java:250)
        at java.awt.Container.validateTree(Container.java:276)
        at java.awt.Container.validateTree(Container.java:282)
        at java.awt.Container.validateTree(Container.java:282)
        at java.awt.Container.validate(Container.java:265)
        at BasherApplet.run(BasherApplet.java:344)
        at java.lang.Thread.run(Thread.java)

Since validate() is called by a window resize, and since validate() calls layoutContainer(), it could be triggered without using a contrived test.