Block scope variables

Question

This will compile

class X
{  
    public static void main(String args[])
    {
        {
            int a = 2;
        }
        {
            int a = 3;
          


        

Answer 1

Java doesn't allow you to have two variables with the same name within scope of one another.

In your second case:

int a = 2;

{
  // the outer 'a' is still in scope
  int a = 3; // so this is a redeclare <-- nooo!
} 

However, in your first case, each a is contained within its own scope, so all is well.