Techniques for generation of Java macro instructions suitable for use in Java computing environments are disclosed. The socket includes a main body having a driving portion and a connecting portion at two ends. Other embodiments have been claimed and described. In the case of multiple-mode delivery, \u201cescalation\u201d rules may specify conditions under which different delivery modes may be sequentially employed. The depth of the annular wall is about of the wavelength of radio waves, and the width of a bottom surface of the annular wall is about to {fraction } of the wavelength of the radio waves.