System.setProperty("abc", "123");

        value = "${abc}";
        assertEquals("123", ResourceUtil.resolve(value));

        value = "xxx${abc}zzz";
        assertEquals("xxx123zzz", ResourceUtil.resolve(value));

        value = "${abc.xyz}";
        assertEquals(value, ResourceUtil.resolve(value));

        System.setProperty("abc.xyz", "789");

        value = "${abc.xyz}";