Java client throws a NPE when the BatchWrite class is initialised with Operation array with null value

[zsfVishnu]

• When the BatchWrite instance was created with an array of Operation type but with null values. Example :

Operation[] ops1 = new Operation[3];
ops1[0] = Operation.put(new Bin(BinName4, 100));
ops1[1] = ExpOperation.read(ResultName1, rexp1, ExpReadFlags.DEFAULT);

• In this case, the 3 element in the array would be null . The BatchWrite class internally tries to access all the elements of the array as

for (Operation op : ops) {
			if (op.type.isWrite) {
				hasWrite = true;
			}
			size += Buffer.estimateSizeUtf8(op.binName) + Command.OPERATION_HEADER_SIZE;
			size += op.value.estimateSize();
		}

• This would cause a crash.
• Adding individual checks doesn't seem helpful since the same array might be passed down to other classes like BatchAttr, hence filtering at constructor level seems to make sense .

[zsfVishnu]

Let me know if these 2 PRs looks good to be merged (latest master jdk21 and jdk 8 )
: #395
: #396

[shrutiverma29]

The same issue can happen on BatchRead as well. Made similar changes for that class as well.
#398
#399

[BrianNichols]

If one of the operations in the array is null, a null pointer exception is generated which is not a crash. This is the intended behavior.

The pull request silently reduces the operations array size if there is a null operation. This will cause errors when the user code retrieves results for each operation because the expected offset in the results may now be different.

[zsfVishnu]

Ok, thanks for the explanation @BrianNichols .