code: public void reinit(final String id,
                       final Object caller,
                       final MessageResources messages,
                       final ActionErrors errors,
                       final String exceptionPname,
                       final boolean clear) {
      this.id = id;
      this.caller = caller;
      this.messages = messages;
      this.errors = errors;
      this.exceptionPname = exceptionPname;
  
      if (clear) {
        msgList.clear();
      }
    }
docs: Generation of errors in the servlet world means adding them to the
  errors object. We need to call this routine on every entry to the
  application
  
  @param id       An identifying name
  @param caller   Used for log identification
  @param messages Resources
  @param errors   Error message will be appended on failure.
  @param exceptionPname Property name for exceptions
  @param clear true to clear list