static boolean isOverflowedToDisk(DiskEntry de, DiskRegion dr,
        DistributedRegion.DiskPosition dp) {
      DiskId did;
      synchronized (de) {
        did = de.getDiskId();
      }
      Object syncObj = did;
      if (syncObj == null) {
        syncObj = de;
      }
      if (syncObj == did) {
        dr.acquireReadLock();
      }
      try {
        synchronized (syncObj) {
          if (de.isValueNull()) {
            if (did == null) {
              synchronized (de) {
                did = de.getDiskId();
              }
              assert did != null;
              return isOverflowedToDisk(de, dr, dp);
            } else {
              dp.setPosition(did.getOplogId(), did.getOffsetInOplog());
              return true;
            }
          } else {
            return false;
          }
        }
      } finally {
        if (syncObj == did) {
          dr.releaseReadLock();
        }
      }
    }
Get the value of an entry that is on disk without faulting it in . It checks for the presence
in the buffer also. This method is used for concurrent map operations and CQ processing

@since GemFire 5.1
geode-core/src/main/java/org/apache/geode/internal/cache/entries/DiskEntry.java