Searching with keywords “most popular programming languages 2013” in any search engine, you’ll find that Java always stays on top 3 of the list. It’s easy to understand because Java is an old programming language, open source, supports many operating systems (such as Linux, Windows…) and is able to run on many devices with slogan “Write once, run everywhere”. There is no question about position of Java or C or C++ but I just wonder how it can be, that Objective C has higher position than C#. A language for about one billion devices is more popular than a language for many billion devices around the world? It’ really weird. However it is not the topic of this post today. Back to Java, with its popularity, of course there are many great open source libraries written in Java. They are all wonderful libraries that any programmer would like to use in his product because of their numerous features and stability.