Transformer or Converter?

Question

I have worked on some project and come across situations where a certain object has to be transformed into another.

In general, these are java classes originated in COBOL that I convert to another type, but with clearer and more intuitive class names, methods and attributes.

I’ve been using the Apache Collections, more specifically the interface Transformer and related utility classes.

I have adopted as class name something like <NomeDoBean>Transformer. My question is:

What’s the difference between Converter and Transformer, in that context?

I know that JSF uses the term Converter. What term to use and why?