37 lines
922 B
Java
37 lines
922 B
Java
// housekeeping/TypeInference.java
|
|
// (c)2021 MindView LLC: see Copyright.txt
|
|
// We make no guarantees that this code is fit for any purpose.
|
|
// Visit http://OnJava8.com for more book information.
|
|
// {NewFeature} Since JDK 11
|
|
|
|
class Plumbus {}
|
|
|
|
public class TypeInference {
|
|
void method() {
|
|
// Explicit type:
|
|
String hello1 = "Hello";
|
|
// Type inference:
|
|
var hello = "Hello!";
|
|
// Works for user-defined types:
|
|
Plumbus pb1 = new Plumbus();
|
|
var pb2 = new Plumbus();
|
|
}
|
|
// Also works for static methods:
|
|
static void staticMethod() {
|
|
var hello = "Hello!";
|
|
var pb2 = new Plumbus();
|
|
}
|
|
}
|
|
|
|
class NoInference {
|
|
String field1 = "Field initialization";
|
|
// var field2 = "Can't do this";
|
|
// void method() {
|
|
// var noInitializer; // No inference data
|
|
// var aNull = null; // No inference data
|
|
// }
|
|
// var inferReturnType() {
|
|
// return "Can't infer return type";
|
|
// }
|
|
}
|