@Override
      public byte getUserBits() {
        byte userBits = 0x0;
        if (isSerialized()) {
          if (isTombstoneToken()) {
            userBits = EntryBits.setTombstone(userBits, true);
          } else if (isInvalidToken()) {
            userBits = EntryBits.setInvalid(userBits, true);
          } else if (isLocalInvalidToken()) {
            userBits = EntryBits.setLocalInvalid(userBits, true);
          } else {
            if (bytes == null) {
              throw new IllegalStateException("userBits==1 and value is null");
            } else if (bytes.length == 0) {
              throw new IllegalStateException("userBits==1 and value is zero length");
            }
            userBits = EntryBits.setSerialized(userBits, true);
          }
        }
        return userBits;
      }
Used to initialize a new disk entry
geode-core/src/main/java/org/apache/geode/internal/cache/entries/DiskEntry.java