Why does easywsdl prepend each class with 3 random characters?

I have been using the easywsdl Android Studio plugin to autogenerate ksoap2 code based on a wsdl.

Each time I generate the code, easywsdl prepends 3 random upper-case characters to the java class names.

Question is why?

These 3 random characters are added in Free account only. For premium, you can define a prefix for classes (or you can generate without any prefix).