Java™ How To Program (Early Objects), Tenth Edition

Logic Errors from Lack of Synchronization

Consider how logic errors can arise if we do not synchronize access among multiple threads manipulating shared mutable data. Our next example (Figs. 23.9–23.13) implements a producer/consumer relationship without the proper synchronization. A producer thread writes the numbers 1 through 10 into a shared buffer—a single memory location shared between two threads (a single int variable called buffer in line 6 of Fig. 23.12 in this example). The consumer thread reads this data from the shared buffer and displays the data. The program’s output shows the values that the producer writes (produces) into the shared buffer and the values that the consumer reads (consumes) from the shared buffer.

Each value the ...