Why can we have only one public class in our program

Question

Why is it that we can specify only one class as public in our source code .................................................
Once i'd put one inner class as public ...which means now i have 2 public classes ..............out of which one is the inner class...what is the use of such public class which can be accessed by only its outer class.........
plz. help

Answer 1

Once i'd put one inner class as public ...which means
now i have 2 public classes ..............out of
which one is the inner class...what is the use of
such public class which can be accessed by only its
outer class.........
plz. helpWrong.
Public inner class can certainly be accessed outside.
You just have to preface it with the name of the outer class.
A.java
=====
public class A {
   AA example = new AA();
   public class AA {
       public int value() { return 5; }
}B.java
=====
public class B {
   public static void main(String[] args) {
      A x = new A ();
      A.AA y = x.example;
      System.out.println(y.value());
}