JAVA EE: Java Tutorial : Java nested classes(Local Classes-Interface)

Tuesday, 12 January 2016

Java Tutorial : Java nested classes(Local Classes-Interface)

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https://www.youtube.com/watch?v=sU7rUq9eZec&list=UUhwKlOVR041tngjerWxVccw

OuterClass.java

public class OuterClass
{

    private String name = "John";

    public void greetInEnglish() 
    {
        /*
         * We cannot declare an interface inside a block.
         */
        interface Hello
        {
           public void greet();
        }
        
        class EnglishHello implements Hello 
        {
            public void greet() 
            {
                System.out.println("Hello " + name);
            }
        }
        
        Hello myGreeting = new EnglishHello();
        myGreeting.greet();
    }
}

LocalClassTest.java

public class LocalClassTest
{
    public static void main(String args[])
    {
        OuterClass outerClass = new OuterClass();
        outerClass.greetInEnglish();
    }

}

Output

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    The member interface Hello can only be defined inside a top-level class or interface or in a static context
    Hello cannot be resolved to a type
    Hello cannot be resolved to a type

    at OuterClass.greetInEnglish(OuterClass.java:11)
    at LocalClassTest.main(LocalClassTest.java:7)