Fix intermittent failure in Balking pattern describe in iluwatar#699

Author: staillebois

balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java

@@ -35,19 +35,23 @@
  */
 public class WashingMachineTest {
 
-  private volatile WashingMachineState machineStateGlobal;
+  private WashingMachineState machineStateGlobal;
 
   @Test
   public void wash() throws Exception {
     WashingMachine washingMachine = new WashingMachine();
     ExecutorService executorService = Executors.newFixedThreadPool(2);
     executorService.execute(() -> {
       washingMachine.wash();
-      machineStateGlobal = washingMachine.getWashingMachineState();
+      if(machineStateGlobal==null) {
+        machineStateGlobal = washingMachine.getWashingMachineState();
+      }
     });
     executorService.execute(() -> {
       washingMachine.wash();
-      machineStateGlobal = washingMachine.getWashingMachineState();
+      if(machineStateGlobal==null) {
+        machineStateGlobal = washingMachine.getWashingMachineState();
+      }
     });
     executorService.shutdown();
     try {