One of the main features in Java 10 in Local Type Inference, which allows us to substitute a type with the var reserved word in our source code. However, in order for this to become a feature that is useful to a developer rather than a feature developers will rue for many years to come, we need to learn how to use it and when to use it properly. This cheat sheet and blog is a reduced version of an blog post that Stuart Marks wrote on the OpenJDK site.