Anyone notice that the Trail: Essential Java Classes Lesson: Threads: Doing Two or More Tasks At Once -
The Producer/Consumer Example produces random results when the author states -
"When an object is locked by one thread and another thread tries to call a synchronized method on the same object, the second thread will block until the object is unlocked."


The results show this not the case: He says the results will be:

Producer #1 put: 0

Consumer #1 got: 0

Producer #1 put: 1

Consumer #1 got: 1

Producer #1 put: 2

Consumer #1 got: 2

Producer #1 put: 3

Consumer #1 got: 3

Producer #1 put: 4

Consumer #1 got: 4

Producer #1 put: 5

Consumer #1 got: 5

Producer #1 put: 6

Consumer #1 got: 6

Producer #1 put: 7

Consumer #1 got: 7

Producer #1 put: 8

Consumer #1 got: 8

Producer #1 put: 9

Consumer #1 got: 9

Hence showing that the consumer is never invoked until the Producer is finished, but my results are random in order - sometimes the consumer consumes prior to the producer - how can this be?

my results:

Consumer #1 got: 0

Consumer #1 got: 1

Producer #1 put: 1

Consumer #1 got: 2

Producer #1 put: 2

Producer #1 put: 3

Consumer #1 got: 3

Consumer #1 got: 4

Producer #1 put: 4

Producer #1 put: 5

Consumer #1 got: 5

Consumer #1 got: 6

Producer #1 put: 6

Producer #1 put: 7

Consumer #1 got: 7

Consumer #1 got: 8

Producer #1 put: 8

Producer #1 put: 9

Consumer #1 got: 9

try for yourselves:

http://java.sun.com/docs/books/tutorial/essential/threads/synchronization.html