code: public String resolveExpression(String expression) throws Exception {
          if (expression == null || expression.length() == 0) {
              return expression;
          }
          final ModelNode request = createRequest("resolve-expression", Address.root());
          request.get("expression").set(expression);
          final ModelNode response = execute(request);
          if (!isSuccess(response)) {
              throw new FailureException(response);
          }
          return getResults(response).asString();
      }
docs: Given a string with possible ${x} expressions in it, this will resolve that expression
  using system property values that are set within the AS JVM itself. If the string
  to resolve has no expressions, or has no expressions that are resolveable, the expression
  string itself is returned as-is (this includes if <code>expression</code> is <code>null</code>).
  
  @param expression string containing zero, one or more ${x} expressions to be resolved
  @return the expression with the expressions resolved using system properties of the AS JVM
  @throws Exception if failed to resolve the expression.