rem: var obj = Components.classes.nsEcho.createInstance(); obj = obj.QueryInterface(Components.interfaces.nsIEcho); return obj; 
add: var clazz = Components.classes["@mozilla.org/js/xpc/test/Echo;1"]; var iface = Components.interfaces.nsIEcho; return new clazz(iface); 
context: function nsNativeEcho(){    var obj = Components.classes.nsEcho.createInstance();    obj = obj.QueryInterface(Components.interfaces.nsIEcho);    return obj;}    
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/8b640618cc61875d42657ed5c7233a84abfea09c/xpctest_echo.js/clean/js/src/xpconnect/tests/js/old/xpctest_echo.js