Why would you think that you should introduce a new class but not even write a single sentence to explain where it comes from? As a programmer for whom Glass development is my first ever foray into Java/Eclipse/Android (not my choice), this threw me off for an extra hour while I tried to figure out if SessionUtils was a Java thing, a package from some other library I should go download, a new class I should write myself, etc. Even a comment in one of the servlet.java files would have greatly reduced the headache this caused. I don’t think one sentence would be “taking too much focus away” from the Mirror API.
For anyone else stumbling on this page, download this file:
and add it to your test.book.glass package.