In brief: According to the Tiobe index of language popularity, the gap between Java and C# is so small that if the current trends remain unchanged, C# will overtake Java in about two months. Of all the languages, Java shows the highest annual decline (3.92%) and has dropped one position compared to October 2022.

Java is currently at number 4 on the Tiobe index of language popularity, with an 8.92% rating, while C# is ranked fifth with a 7.71% rating. Java was ranked top in April 2020, its highest position since 2001, and dropped to number 4 in September 2023, its lowest position (since 2001) after being overtaken by C++, C, and Python.

In the ranking, C Sharp shows the highest gain of 3.29%, while Java shows the highest decline of all the languages annually (3.92%) and has dropped one position compared to October 2022. The two programming languages belong to the 'C-family' and have gone head-to-head for more than 20 years now.

According to Tiobe, which specializes in assessing and tracking software quality, Java's downfall is attributed mainly to Oracle's move to introduce a paid license after the release of version 8 of Java.

On the other hand, Microsoft's C Sharp is free and open source even though Microsoft had earlier released the language along with Visual Studio and .NET Framework, which were all closed-source. It later released Visual Studio Code and the unified .NET platform, all of which support C# and are open source.

Another reason for Java's decline, according to Tiobe, is that its definition has not changed much in the past, and its direct competitor and alternative from JetBrains, Kotlin, is easier to use and completely free.

The rankings are based on the Tiobe programming community index, which is updated monthly and indicates how popular programming languages are. The ratings are based on the number of third-party vendors, courses, and skilled engineers. Yahoo!, Bing, Google, Rakuten, and Etsy are some of the 25 popular search engines used for the calculation, and the ratings are calculated by counting the number of hits.

Tiobe says that the index does not focus on the best programming language, and you can use it to check whether your programming skills are up to date or to decide the programming language you need to pick.

Image credit: Christopher Gower