Doubt on Inner class

[Chitra AP]

I am kind of confused here. Here is the program:

class A {
private static int counter;
 
public static int getCounter() {
return counter++;
}
 
private static int innerCounter;
 
public static int getInnerCounter() {
return innerCounter++;
}
 
private String name;
 
A() {
name = "A" + getCounter();
}
 
class B {
private String name;
 
B() {
name = "B" + getInnerCounter();
System.out.print(A.this.name + name);
}
}
 
void m1() {
new A().new B();
}
 
void m2() {
this.new B();
}
 
void m3() {
new B();
}
 
public static void main (String[] args) {
A a1 = new A();
a1.m1();
a1.m2();
a1.m3();
}
}

It prints A1B0A0B1A0B2. I understood until how it prints A1B0 , after that I thought it would print A1B1A1B2, but it prints A0B1A0B2. How?
When a1.m2() executed, A.this.name would be A1, correct ? I don't understand when it became A0. Please help me to understand the code correctly.

Thank you so much.

[Shweta R Dhaneshwar]

Hi Chitra,
I suppose it goes like this.Initially counter and innerCounter are both set to 0.In the main method a new object of A is created.So the constructor of class A sets variable name to A0 and sets outer to 1..So at this point outer is 1 and innerCounter is 0.Next in the main ,m1 is called on object of class A.In m1 a new object of A is created setting name to A1 and incrementing outer to 2.Method m1 calls constructor of inner class on this newly created object of class A.Constructor in class B sets name in inner class to B0 and increments innerCounter to 1.In the B's constructor the println statement prints A1 and B0.Its A1 because in method m1 its the new object of the enclosing class on which the constructor of B gets called.In method m2 and m3 its the first object of A on which constructors of B is called.I hope you will be able to figure it out now.If you still find this confusing...let me know.

all the best

[Lalitha Gottumukkula]

Try making 'name' variable of class A as 'static' and see the output !!

Thanks,
Lalitha.

[Chitra AP]

I got it. Thanks.

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[amit taneja]

good question

[S Santhosh]

Good question chitra, tricks the brain to catch a static variable with a non static variable. I understood only after seeing the output, here it is :

Counter = 0
Inside m1
Counter = 1
A1B0
Inside m2
A0B1
Inside m3
A0B2

Thanks guys,
San
[ June 08, 2005: Message edited by: San Sreeds ]