use background task executor to refresh wind estimation track cache

Change-Id: I6fa08dadde0893ddddbac7f09a1d86e98a8299c7

java/com.sap.sse.test/META-INF/MANIFEST.MF

@@ -6,4 +6,4 @@ Bundle-Version: 1.0.0.qualifier
 Bundle-Vendor: SAP
 Fragment-Host: com.sap.sse
 Bundle-RequiredExecutionEnvironment: JavaSE-1.8
-Require-Bundle: org.junit4
+Require-Bundle: org.junit4;bundle-version="4.8.2"

java/com.sap.sse.test/src/com/sap/sse/test/AbortingTaskScheduledAtFixedRateTest.java

@@ -15,6 +15,11 @@ public class AbortingTaskScheduledAtFixedRateTest {
     private static final int RATE_IN_MILLIS = 100;
     private static final Logger logger = Logger.getLogger(AbortingTaskScheduledAtFixedRateTest.class.getName());
     
+    /**
+     * Asserts that calling {@link ScheduledFuture#cancel(boolean)} on an object returned by
+     * {@link ScheduledExecutorService#scheduleAtFixedRate(Runnable, long, long, TimeUnit)} keeps the
+     * task from executing again.
+     */
     @Test
     public void testAbortTaskScheduledAtFixedRate() throws InterruptedException {
         final int[] executions = new int[1];