Sync: add isServerAvailable.

Author: greenrobot-team

objectbox-java/src/main/java/io/objectbox/sync/Sync.java

@@ -19,6 +19,13 @@ public static boolean isAvailable() {
         return BoxStore.isSyncAvailable();
     }
 
+    /**
+     * Returns true if the included native (JNI) ObjectBox library supports Sync server.
+     */
+    public static boolean isServerAvailable() {
+        return BoxStore.isSyncServerAvailable();
+    }
+
     /**
      * Start building a sync client. Requires the BoxStore that should be synced with the server,
      * the URL and port of the server to connect to and credentials to authenticate against the server.

tests/objectbox-java-test/src/test/java/io/objectbox/sync/SyncTest.java

@@ -29,7 +29,7 @@ public void clientIsNotAvailable() {
      */
     @Test
     public void serverIsNotAvailable() {
-        assertFalse(BoxStore.isSyncServerAvailable());
+        assertFalse(Sync.isServerAvailable());
     }
 
     @Test