I always get a build message "- Warning: .. first argument is not a string
how it is programmed correctly or
is it possible to disable the warning?
var checks = qx.core.Environment.getChecks();
var keys = Object.keys(checks);
for (var i = 0; i < keys.length; i++)
var key = keys[i];
var value = qx.core.Environment.get(key); /* <--- problem line */
First off, to program correctly you shouldn't do this at all :-). There is no clean and idiomatic way to do what you are trying. The whole concept of the Environment class is to avoid loading all the environment checks as it would bloat application code, but rather to pick only the checks that are necessary for an application. Here is some background ...
Each Environment key depends on a specific qooxdoo module that calculates its value (or, that implements its "check"). For an application the Generator infers this module from the argument to the Environment.get() call, but can only do so if the argument is a string literal like "browser.name" or "css.borderradius". As you are using a variable the Generator cannot make this inference, and your program will end up throwing a run time exception because of a missing module.
BTW: Environment.getChecks() is an internal method and you shouldn't call it, and you won't usually be able to call it in the build version of your code.