Java default Interface Methods

Question

Here is my simple code from a Java Tutorial.

public interface AnimalIntf {

    default public String identifyMyself(){
        return "I am an animal.";
    }

}

I get an error: illegal start of type interface methods cannot have body. The method is default and the default keyword is used at the beginning of the method signature. Could you please explain to me what is wrong?

Surprisingly, you seem to be the first person to ask this question (or maybe the SO search is so useless it can't find the duplicate). — Jeffrey Bosboom
– Jeffrey Bosboom, Commented Oct 23, 2014 at 19:57
Well, Oracle’s tutorial says it on the start page: “The Java Tutorials primarily describe features in Java SE 8. For best results, download JDK 8” — Holger
– Holger, Commented Oct 27, 2014 at 9:31

Jeffrey Bosboom · Accepted Answer · 2014-10-23 19:55:06Z

5

Default interface methods were introduced in Java 8, so you need a JDK that supports Java 8 or later.

answered Oct 23, 2014 at 19:55

Jeffrey Bosboom

13.7k16 gold badges83 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

JustinKSU · Accepted Answer · 2014-10-23 19:55:41Z

1

You must use Java 8 or above to have default implementations in interfaces. Instead you could use an abstract class. But even then, you wouldn't use the default keyword.

answered Oct 23, 2014 at 19:55

JustinKSU

5,0192 gold badges32 silver badges53 bronze badges

2 Comments

Jeffrey Bosboom Over a year ago

Oh, you meant if you're using an abstract class instead, you don't use default there. Sorry about that.

Yuliana Over a year ago

I have found this, the link could be helpful while determining which one to use, an interface or an abstract class: docs.oracle.com/javase/tutorial/java/IandI/abstract.html

Yuliana · Accepted Answer · 2014-10-23 22:06:16Z

0

Strange things are happening... After the JDK update to version 8 both on computer and in IDE settings, the code compiles OK, but the IDE still marks the line

default public String identifyMyself(){

as error. And there were still errors while trying to use the interface, asking to override the default method in the class that implements the interface.

public class Dragon implements Animal{    
}

2 hours later I got tired of trying to fix my NetBeans v.6.9.1 and downloaded NetBeans v8.0.1. Now I am fine :)

answered Oct 23, 2014 at 22:06

Yuliana

311 silver badge3 bronze badges

Collectives™ on Stack Overflow

Java default Interface Methods

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related