code: @WebMethod(operationName = "getVMUser")
      public VmUser getVMUser(@WebParam(name = "user") final String username,
              @WebParam(name = "pass") final String password) throws VMException {
          VmUser user = isValidUser(username, password);
          if (user == null) {
              throw new VMException("Invalid username and/or password!");
          }
          return user;
      }
docs: Web service operation
  
  @param username Username
  @param password Password
  @return User with provided credentials or null if invalid.
  @throws com.validation.manager.core.VMException