With this post I am starting my blog, and I dedicate it (like probably the next few ones) to topics I am encountering during the preparation of the Java Professional Certification exam. Even if you probably have been using Java for many years, Java certification offers an opportunity to discover details about the language and its features. In the following notes I am collecting a few points that I found at least not obvious, either because I never had the chance to look into them before, or because they showed some peculiar behavior worth keeping in mind. The following notes refer to Java 7.