code: public Throwable getOriginalException() throws ExceptionInstantiationException {
          Throwable prevEx = null;
          if (previousExceptionInfo != null) {
              prevEx = previousExceptionInfo.getOriginalException();
              if (prevEx == null) {
                  prevEx = getPreviousException();
              }
          }
          return prevEx;
      }
docs: Get the original exception in a possible chain of exceptions.
  If no previous exceptions have been chained, null will be returned.
  
  @exception com.ibm.websphere.exception.ExceptionInstantiationException
  An exception occurred while trying to instantiate an exception object.
  If this exception is thrown, the relevant information can be retrieved
  by using the getPreviousExceptionInfo() method.
  
  @return java.lang.Throwable The first exception in a chain of
  exceptions. If no exceptions have been chained, null will be returned.