The Blink project includes three thread groups, each of which is accompanied by the 

glyph:
file:/your-installation-directory/jws/Blink/-threadGroup--contains threads directly related to the Blink project
You'll see the following:
The glyph accompanying a thread is an additional clue as to the state of the thread. Possible glyphs you might come across include:

The thread is suspended.

The thread is stopped at a breakpoint.

The state of the thread cannot be determined.

The thread is a zombie.

The thread is running.

The thread is sleeping.

The thread is waiting on a conditional variable.
Blink.paint, which was executing when the program stopped, is at the top of the stack. The stack frame is highlighted so you can easily tell where the program stopped. Each stack frame is accompanied by the 
glyph.
glyph.
word variable.
glyph.
Next lesson: