Java 11 and 12 – New Features

Summary

In this chapter, we covered local variable inference, or var, as introduced in Java 10. The var type enables you to drop the explicit data type for a local variable in a method. We covered the various dos and don'ts for the usage of var. Limited to local variables, variables defined using var must be initialized with a value. They can be used with all types of variables—primitives and objects. Variables defined with var can also be passed to methods and returned from methods; method declaration compatibility rules apply.

To avoid risking your type safety with generics, ensure that you pass relevant information when using var with generics. Although it doesn't make a lot of sense, the use of explicit casting is allowed with variables ...