List<BatchMutation> batchMutations = new ArrayList<BatchMutation>();
// Mutations to rowA. You can't mix delete and put anymore.
List<Mutation> rowAmutations = new ArrayList<Mutation>();
rowAmutations.add(new Mutation(true, columnAname, null, true));
batchMutations.add(new BatchMutation(rowAname, rowAmutations));
rowAmutations = new ArrayList<Mutation>();
rowAmutations.add(new Mutation(false, columnBname, valueCname, true));
batchMutations.add(new BatchMutation(rowAname, rowAmutations));
// Mutations to rowB
List<Mutation> rowBmutations = new ArrayList<Mutation>();
rowBmutations.add(new Mutation(false, columnAname, valueCname, true));
rowBmutations.add(new Mutation(false, columnBname, valueDname, true));
batchMutations.add(new BatchMutation(rowBname, rowBmutations));
return batchMutations;
}