You should reply to the same thread instead of starting a new one on the same
issue.

First of all, there is no java.io in the code you posted, so the posted code
pretty certainly is not "probably ... the problem", since the error clearly
comes from a java.io.Writer. You should conclude from the error message that
code involved with a Writer is at fault, not that completely unrelated code is
involved.

Secondly, your reassignment of "myList" to the result of the method call is
redundant; it already points to the same list anyway.

Thirdly, it looks like what you need is a Set, not a List. Consequently,

fourthly, you should not name a variable ("classnamevalueslist") with its
implementation as part of the name. What sense does it make to declare

Set<String> classnamevalueslist;
?

And isn't everything a "value"? Putting "value" in the name provides no
specificity.

You should name the variable (using conventional camelCase) "classNames" or
something like that. Then you can change from Set to List to whatever without
having to rename everything.

Why a Set and not a List? Check out the Javadocs for those interfaces.

Speaking of interfaces,

fifthly, usually you should declare a variable with the interface type, and
instantiate it with the concrete type, as:

Set<String> classNames = new HashSet<String> ();

Unless you absolutely require the characteristics of a particular
implementation, this idiom provides more flexibility for plugin changes (e.g.,
to a TreeSet).

Finally, to answer your main question we would need to see the code that was
actually involved in the error. On the face of it, something is writing the
results of a recursive method that has no termination condition.

- Lew