Q1: What will be the output of the program?

public class Test178 
{ 
    public static void main(String[] args) 
    {
        String s = 'foo'; 
        Object o = (Object)s; 
        if (s.equals(o)) 
        { 
            System.out.print('AAA'); 
        } 
        else 
        {
            System.out.print('BBB'); 
        } 
        if (o.equals(s)) 
        {
            System.out.print('CCC'); 
        } 
        else 
        {
            System.out.print('DDD'); 
        } 
    } 
}

ANS:A - AAACCC

The output is the same even when comparing with another string that only its value is the same (but in such a case operaton == returns false), since o object points now to the equals method of the instance of String that doesn't care about addresses difference :

String s1 = new String("foo");
String s2 = new String("foo");
Object o = (Object)s1;
if (s2.equals(o))
{
System.out.print("AAA");
}
else
{
System.out.print("BBB");
}
if (o.equals(s2))
{
System.out.print("CCC");
}
else
{
System.out.print("DDD");
}