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"); 
        } 
    } 
}

public class Test138 
{ 
    public static void stringReplace (String text) 
    {
        text = text.replace ('j' , 'c'); /* Line 5 */
    } 
    public static void bufferReplace (StringBuffer text) 
    { 
        text = text.append ("c");  /* Line 9 */
    } 
    public static void main (String args[]) 
    { 
        String textString = new String ("java"); 
        StringBuffer textBuffer = new StringBuffer ("java"); /* Line 14 */
        stringReplace(textString); 
        bufferReplace(textBuffer); 
        System.out.println (textString + textBuffer); 
    } 
}

class A 
{ 
    public A(int x){} 
} 
class B extends A { } 
public class test 
{ 
    public static void main (String args []) 
    {
        A a = new B(); 
        System.out.println("complete"); 
    } 
}

1. Error
2. Event
3. Object
4. Throwable
5. Exception
6. RuntimeException

public class ExceptionTest 
{ 
    class TestException extends Exception {} 
    public void runTest() throws TestException {} 
    public void test() /* Point X */ 
    { 
        runTest(); 
    } 
}

public class MyProgram 
{
    public static void throwit() 
    {
        throw new RuntimeException();
    }
    public static void main(String args[])
    {
        try 
        {
            System.out.println("Hello world ");
            throwit();
            System.out.println("Done with try block ");
        }
        finally 
        {
            System.out.println("Finally executing ");
        }
    }
}

String x = new String("xyz");
String y = "abc";
x = x + y;

public class ExamQuestion7 
{  
    static int j; 
    static void methodA(int i)
    {
        boolean b; 
        do
        { 
            b = i<10 | methodB(4); /* Line 9 */
            b = i<10 || methodB(8);  /* Line 10 */
        }while (!b); 
    } 
    static boolean methodB(int i)
    {
        j += i; 
        return true; 
    } 
    public static void main(String[] args)
    {
        methodA(0); 
        System.out.println( "j = " + j ); 
    } 
}

public class Test 
{ 
    public static void main(String[] args) 
    {
        final StringBuffer a = new StringBuffer(); 
        final StringBuffer b = new StringBuffer(); 

        new Thread() 
        { 
            public void run() 
            {
                System.out.print(a.append("A")); 
                synchronized(b) 
                { 
                    System.out.print(b.append("B")); 
                } 
            } 
        }.start(); 
            
        new Thread() 
        {
            public void run() 
            {
                System.out.print(b.append("C")); 
                synchronized(a) 
                {
                    System.out.print(a.append("D")); 
                } 
            } 
        }.start(); 
    } 
}

String a = "newspaper";
a = a.substring(5,7);
char b = a.charAt(1);
a = a + b;
System.out.println(a);

public class BoolTest 
{
    public static void main(String [] args) 
    {
        int result = 0;

        Boolean b1 = new Boolean("TRUE");
        Boolean b2 = new Boolean("true");
        Boolean b3 = new Boolean("tRuE");
        Boolean b4 = new Boolean("false");

        if (b1 == b2)  /* Line 10 */
            result = 1;
        if (b1.equals(b2) ) /* Line 12 */
            result = result + 10;
        if (b2 == b4)  /* Line 14 */
            result = result + 100;
        if (b2.equals(b4) ) /* Line 16 */
            result = result + 1000;
        if (b2.equals(b3) ) /* Line 18 */
            result = result + 10000;

        System.out.println("result = " + result);
    }
}