//checkAndPut looking for a null value
put = new Put(row1);
put.add(fam1, qf1, val1);
res = region.checkAndMutate(row1, fam1, qf1, CompareOp.EQUAL,
new NullComparator(), put, lockId, true);
assertTrue(res);
} finally {
HRegion.closeHRegion(this.region);
this.region = null;
}