Java 11 and 12 – New Features

Type inference with var

The following lines of code show how local variables (and all other variables) were defined prior to Java 10:

String name = "Java Everywhere"; 
LocalDateTime dateTime = new LocalDateTime.now();

Starting with Java 10, by using var, you can drop the mandatory explicit type in the declaration of local variables, as follows:

var name = "Java Everywhere";            // variable 'name' inferred as                                          // String 
var dateTime = new LocalDateTime.now();  // var 'dateTime' inferred as                                          // LocalDateTime 

Does it look like the preceding code doesn't offer a lot of benefits? Imagine you could take the following code:

HashMap<Integer, String> map = new HashMap<Integer, String>(); 

And replace it with this code, instead:

var map = new HashMap<Integer, ...