Java 13 Revealed: For Early Adoption and Migration

© Kishori Sharan 2019

K. SharanJava 13 Revealedhttps://doi.org/10.1007/978-1-4842-5407-3_1

1. Local Variable Type Inference

Kishori Sharan¹ 

(1)

Montgomery, AL, USA

 

In this chapter, you will learn

• What type inference is

• What local variable type inference is

• What the restricted type name var is

• The rules to use var to declare local variables, indexes of for-each loop and for loop, and formal parameters for implicitly typed lambda expressions

What Is Type Inference?

Suppose you want to store a person ID, say, 10, in a variable. You would declare the variable like

int personId = 10;

To store a list of person IDs, you would declare a variable like

ArrayList<Integer> personIdList = new ArrayList<Integer>();

How about rewriting these variable declarations as follows? ...