JAVA 10 exciting Feature : Local Variable Type Inference

JAVA 10 :  Local Variable Type Inference

Like JavaScript, Kotlin, and Scala, now Java 10 introduced var keyword that allows you to declare a local variable without specifying its type. The type will be inferred from context. For example, when you say var name = "Silan", then the compiler will already know the type is String.

The var keyword can only be used for local variables, i.e. variables inside methods or code blocks — you cannot use it for member variable declaration inside the class body.

But like Python, it doesn't make Java a dynamically typed language. Java is still a statically typed language, and once the type is assigned, you cannot change it. For example, var name = "Silan" is ok, but if we will assign name =100; then it is not right.

This is one of the most eye-catching features of Java 10. It reduces the amount of boilerplate code needed to declare local variables in Java.

Overall we can say in a single statement that we can declare variables without specifying the associated type. A declaration such as:

List<String> l=new ArrayList<String>();

Can be written as var l=new ArrayList<String>();

Note: Type Inference is not a new Concept in JAVA but it is a new concept for local variables.