Block scope variables

Question

This will compile

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


        

Answer 1

public static void main(String args[])
{
    int a = 2; // I know a
    // I know a
    {
        // I know a
        int a = 3; // There can be only one a!
    }       
}

In the example above you declared a in you method main(). From the declaration till the end of the method, a is declared. In this case you cannout redeclare a in you codeblock.

Below, you declare a in a block. It is only known insside.

public static void main(String args[])
{
    { 
        int a = 2; // I know a
        // I know a
    }
    // Who is a?
    {

        int a = 3; // I know a!
    }       
}