private void setInUseByTransaction(final boolean v) {
    if (v) {
      setBits(IN_USE_BY_TX);
    } else {
      clearBits(~IN_USE_BY_TX);
    }
  }
Any bits in "bitMask" that are 0 will be cleared.
geode-core/src/main/java/org/apache/geode/internal/cache/entries/AbstractRegionEntry.java