default method in interfaces in java

Question

I am attempting to understand default methods in interfaces in Java using the following code, but I am unable to compile it:

public interface A {
    default void foo(){
       System.out.println("Calling A.foo()");
    }
}

public class Clazz implements A {
}

class c
{
    public static void main(String[]args)
    {
        Clazz clazz = new Clazz();
        clazz.foo(); // Calling A.foo()
    }
}

The compiler produced the following output:

c.java:2: error: illegal start of type
    default void foo(){
    ^
c.java:2: error: = expected
    default void foo(){
            ^
c.java:2: error: ';' expected
    default void foo(){
                ^
c.java:2: error: illegal start of type
    default void foo(){
                    ^
c.java:2: error:  expected
    default void foo(){
                     ^
c.java:2: error: = expected
    default void foo(){
                      ^
c.java:2: error: ';' expected
    default void foo(){
                       ^
c.java:3: error: illegal start of type
       System.out.println("Calling A.foo()");
             ^
c.java:3: error: = expected
       System.out.println("Calling A.foo()");
                 ^
c.java:3: error:  expected
       System.out.println("Calling A.foo()");
                         ^
c.java:3: error: illegal start of type
       System.out.println("Calling A.foo()");
                          ^
c.java:5: error: class, interface, or enum expected
       }

I am unable to understand these errors. How can I correct the problems in my code?

Answer 1

default modifier doesn't work for java version older than 8, so make sure you're using the right compiler for your source code.