Nested classes java

Question

I have the following code:

public class A
{
    private class B
    {
        public String a = "";
        public B(String a)
        {
          System.out.println("hello");
          this.a = a;
        }
    }

    public A()
    {
        System.out.println("bla");
        B b = new B("what's up?");
        System.out.println("world");
    }

    public static void main(String[] args)
    {
       new A();
    }
}

For some reason, only the "bla" is printed, the other prints aren't printed. I'm loading this class file with jni using dynamic class loading and calling the main function.

What am I doing wrong?

Works fine, as long as `someFunc()` is called... something else you're not showing us? — Ryan J, Mar 10 '15 at 20:43
I ran it on my computer (with a main function added) and it works fine it prints `bla hello world` — Roan, Mar 10 '15 at 20:43
There is more code that calls someFunc, but when it gets to the part where a new instance of the nested class is created, it doesn't work. — John Doe, Mar 10 '15 at 20:50
Create an example that shows the problem which we can execute ourselves. 90% of the time you'll find the problem on your own instead of showing us something we can't do anything with. — Jeroen Vannevel, Mar 10 '15 at 20:52
"I'm loading the A class with jni using dynamic class loading." - doesn't seem so from your code. — adarshr, Mar 10 '15 at 21:02
Your code as posted worked just fine for me as well. You need to create a [mcve](http://stackoverflow.com/help/mcve) that shows the error. — azurefrog, Mar 10 '15 at 21:04

score 1 · Answer 1 · answered Mar 10 '15 at 21:18

there you go, this code works:

public class A
{
    static class B
    {
        public String a = "";
        public B(String a)
        {
          System.out.println("hello");
          this.a = a;
        }
    }

    public A()
    {
        System.out.println("bla");
        B b = new B("what's up?");
        System.out.println("world");
    }

    public static void main(String[] args)
    {
       new A();
       A.B myAB = new A.B("hello");
    }
}

OUTPUT:

bla
hello
world
hello

if you want to print in class B the actual string "a", then change public String a = ""; to System.out.println(a); in which case you will get

bla
what's up?
world
hello

since "what's up?" is passed to class B

See the Javadocs for nested classes, it will help you a lot I think: http://docs.oracle.com/javase/tutorial/java/javaOO/nested.html

Nested classes java

1 Answers1