@Override
    public void run() {
      long keyId = 0;
      for (int i = 0; i < 10000; i++) {
        keyId = ((LocalRegion) region).getDiskRegion().newOplogEntryId();
        keyIds.add(keyId);
      }
    }
Testing methods for SimpleDiskRegion.java api's

@since GemFire 5.1
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/SimpleDiskRegionJUnitTest.java