[Java] Avoid memory allocation at varDataDisplay

[ariksher-nex]

varDataDisplay - use method getVarFieldName(Appendable) - no memory allocation. unlike calling method varFieldName where it allocates memory (new byte[] and new String).

[mjpt777]

This generates code which does not compile.

[ariksher-nex]

This generates code which does not compile.

yep, fixed it. apparently code is bit different for UTF and ASCII.

[mjpt777]

The UTF-8 implementation allocates too. I'm not in favour of supporting this as it is too brittle.

[ariksher-nex]

The UTF-8 implementation allocates too. I'm not in favour of supporting this as it is too brittle.

I'm using at my project ASCII chars and I'm willing to use the method appendTo that sits on the generated xxxDecoder class(es), which is very useful for logging incoming messages.

[mjpt777]

I've pushed a more obvious changes which saves on allocation.

[ariksher-nex]

I've pushed a more obvious changes which saves on allocation.

seen your commit and it paratially solves the problem see my comment there
391527a#r35648950

[mjpt777]

A better approach for you to take is to use the append version if and only iff the encoding is ASCII otherwise output as is at present.