Use auto-boxing

Change-Id: I20b7073a49cacdb552ad16389f26b60ed407390a

@@ -84,7 +84,7 @@ public class DefaultDatabaseState implements DatabaseState<String, byte[]> {
         }
         nextVersion = context.get("nextVersion");
         if (nextVersion == null) {
-            nextVersion = new Long(0);
+            nextVersion = 0L;
             context.put("nextVersion", nextVersion);
         }
     }

@@ -65,7 +65,7 @@ public class TimestampedTest {
 
     @Test
     public final void testValue() {
-       final Integer n = Integer.valueOf(42);
+       final Integer n = 42;
        Timestamped<Integer> tsv = new Timestamped<>(n, TS_1_1);
        assertSame(n, tsv.value());