concurrent test

whatsmars-common/src/test/java/org/hongxi/java/util/concurrent/CallableTest.java

@@ -20,5 +20,6 @@ public class CallableTest {
         long begin = System.currentTimeMillis();
         System.out.println(future.get());
         System.out.println(System.currentTimeMillis() - begin);
+        executorService.shutdown();
     }
 }

whatsmars-common/src/test/java/org/hongxi/java/util/concurrent/FutureTaskTest.java

@@ -25,5 +25,6 @@ public class FutureTaskTest {
         if (!task2.isCancelled()) {
             System.out.println(task2.get());
         }
+        executorService.shutdown();
     }
 }

whatsmars-common/src/test/java/org/hongxi/java/util/concurrent/RunnableTest.java

@@ -18,5 +18,6 @@ public class RunnableTest {
         Future<String> future = executorService.submit(() ->
                 System.out.println("..."), "world");
         System.out.println(future.get());
+        executorService.shutdown();
     }
 }