Java 11 and 12 – New Features

Breaking existing code

As of Java 10, var is a restricted local variable type and cannot be used for type declarations. Code that uses var as the name of a class, interface, method, method parameters, or variables, will no longer compile in JDK 10 and later releases.

The following is an example of code that uses var at multiple places and won't compile:

class var {}          // can't use var as class nameinterface var {}      // can't use var as interface nameclass Demo {    int var = 100;               // can't use var as instance variable                                  // name    static long var = 121;       // can't use var as static variable                                  // name    void var() {                 // can't use var as method name        int var = 10;            // cant use var as the name of a local                                  // variable    } void aMethod(String var) {} // can't ...