var (local type inference)

Definition

var lets the compiler work out the type of a local variable from the value on the right, so you do not repeat a long type name. The variable is still strongly typed; it is just not written out.

Example code

Less typing, same safety

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

class Demo {
    public static void main(String[] args) {
        var names = new ArrayList<String>();          // inferred as ArrayList<String>
        names.add("Asha");

        var ages = new HashMap<String, Integer>();    // inferred as HashMap<String, Integer>
        ages.put("Asha", 30);

        for (var entry : ages.entrySet()) {           // handy for long types
            System.out.println(entry.getKey() + " -> " + entry.getValue());
        }

        // names = 5;                                 // still a compile error: the type is fixed
        System.out.println(names);
    }
}

// Output:
// Asha -> 30
// [Asha]