DataInputStream readUTF related field initialization

[Robert Marcano]

Greetings. DataInputStream has some fields with the comment "working 
arrays initialized on demand by readUTF" but these fields are being 
initialized at object instantiation.

On the other hand DataOutputStream has one field with a likewise comment 
initialized to null.

I think DataInputStream could be optimized the same way as 
DataOutputStream and help in the memoty footprint of DataInputStream 
when used for other reads not related to readUTF.

Sounds reasonable?