Summary breakpoint on JAVA class

Add breakpoints skills
first to see if the button is pressed into the monitor after
the second step, to verify whether the thread is started;
the third step while circulating among the
fourth update subclass paint method
to see if he entered
and then found myCanvas.invalidate ();
write code Note:
when determining the use of precautionary statements must have been written to ensure the integrity of the sentence
must take plus sign, for example;