docs: private void setSubjectPrincipals() {
          if (null != userPrincipal) {
              this.subject.getPrincipals().add(userPrincipal);
          }
          if (null != rolePrincipals) {
              for (Principal rolePrincipal : rolePrincipals) {
                  this.subject.getPrincipals().add(rolePrincipal);
              }
          }
      }