Java Programming

Java Programming

Java.lang Class has 32 Questions
What is the value of "d" after this line of code has been executed?

2
3
4
2.5
What will be the output of the program?
String x = new String("xyz");
y = "abc";
x = x + y;
how many String objects have been created?

2
3
4
5
Which of the following would compile without error?

int a = Math.abs(-5);
int b = Math.abs(5.0);
int c = Math.abs(5.5F);
int d = Math.abs(5L);
What will be the output of the program?
public class WrapTest 
{
    public static void main(String [] args) 
    {
        int result = 0;
        short s = 42;
        Long x = new Long("42");
        Long y = new Long(42);
        Short z = new Short("42");
        Short x2 = new Short(s);
        Integer y2 = new Integer("42");
        Integer z2 = new Integer(42);

        if (x == y) /* Line 13 */
            result = 1;
        if (x.equals(y) ) /* Line 15 */
            result = result + 10;
        if (x.equals(z) ) /* Line 17 */
            result = result + 100;
        if (x.equals(x2) ) /* Line 19 */
            result = result + 1000;
        if (x.equals(z2) ) /* Line 21 */
            result = result + 10000;

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

result = 1
result = 10
result = 11
result = 11010
Which of the following are valid calls to Math.max?
  1. Math.max(1,4)
  2. Math.max(2.3, 5)
  3. Math.max(1, 3, 5, 7)
  4. Math.max(-1.5, -2.8f)

1, 2 and 4
2, 3 and 4
1, 2 and 3
2, 3 and 4
What will be the output of the program?
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);
    }
}

0
1
10
10010
public class Myfile 
{ 
    public static void main (String[] args) 
    {
        String biz = args[1]; 
        String baz = args[2]; 
        String rip = args[3]; 
        System.out.println("Arg is " + rip); 
    } 
}
Select how you would start the program to cause it to print: Arg is 2

java Myfile 222
java Myfile 1 2 2 3 4
java Myfile 1 3 2 2
java Myfile 0 1 2 3
What will be the output of the program?
public class ObjComp 
{
    public static void main(String [] args ) 
    {
        int result = 0;
        ObjComp oc = new ObjComp();
        Object o = oc;

        if (o == oc)  
            result = 1;
        if (o != oc)  
            result = result + 10;
        if (o.equals(oc) )  
            result = result + 100;
        if (oc.equals(o) )  
            result = result + 1000;

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

1
10
101
1101
What will be the output of the program?
public class Example 
{
    public static void main(String [] args) 
    {
        double values[] = {-2.3, -1.0, 0.25, 4};
        int cnt = 0;
        for (int x=0; x < values.length; x++) 
        {
            if (Math.round(values[x] + .5) == Math.ceil(values[x])) 
            {
                ++cnt;
            }
        }
        System.out.println("same results " + cnt + " time(s)");
    }
}

same results 0 time(s)
same results 2 time(s)
same results 4 time(s)
Compilation fails.
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"); 
        } 
    } 
}

AAACCC
AAADDD
BBBCCC
BBBDDD
What will be the output of the program?
String x = "xyz";
x.toUpperCase(); /* Line 2 */
String y = x.replace('Y', 'y');
y = y + "abc";
System.out.println(y);

abcXyZ
abcxyz
xyzabc
XyZabc
What will be the output of the program?
int i = (int) Math.random();

i = 0
i = 1
value of i is undetermined
Statement causes a compile error
What will be the output of the program?
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"); 
    } 
}

It compiles and runs printing nothing
Compiles but fails at runtime
Compile Error
Prints "complete"
What will be the output of the program?
int i = 1, j = 10; 
do 
{
    if(i++ > --j) /* Line 4 */
    {
        continue; 
    } 
} while (i < 5); 
System.out.println("i = " + i + "and j = " + j); /* Line 9 */

i = 6 and j = 5
i = 5 and j = 5
i = 6 and j = 6
i = 5 and j = 6
What will be the output of the program?
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 ); 
    } 
}

j = 0
j = 4
j = 8
The code will run with no output
What will be the output of the program?
try 
{
    Float f1 = new Float("3.0");
    int x = f1.intValue();
    byte b = f1.byteValue();
    double d = f1.doubleValue();
    System.out.println(x + b + d);
}
catch (NumberFormatException e) 
{
    System.out.println("bad number");
}

9.0
bad number
Compilation fails on line 13.
Compilation fails on line 14.
What will be the output of the program?
class Q207 
{ 
    public static void main(String[] args) 
    {
        int i1 = 5; 
        int i2 = 6; 
        String s1 = "7"; 
        System.out.println(i1 + i2 + s1); /* Line 8 */
    } 
}

18
117
567
Compiler error
What will be the output of the program?
public class SqrtExample 
{
    public static void main(String [] args) 
    {
        double value = -9.0;
        System.out.println( Math.sqrt(value));
    }
}

3.0
-3.0
NaN
Compilation fails.
What will be the output of the program?
String s = "ABC"; 
s.toLowerCase(); 
s += "def"; 
System.out.println(s);

ABC
abc
ABCdef
Compile Error
What will be the output of the program?
public class NFE 
{
    public static void main(String [] args) 
    {
    String s = "42";
        try 
        {
            s = s.concat(".5");  /* Line 8 */
            double d = Double.parseDouble(s);
            s = Double.toString(d);
            int x = (int) Math.ceil(Double.valueOf(s).doubleValue());
            System.out.println(x);
        }
        catch (NumberFormatException e) 
        {
            System.out.println("bad number");
        }
    }
}

42
42.5
43
bad number
What will be the output of the program?

-2
NaN
Compile Error
Runtime Exception
What will be the output of the program?
interface Foo141 
{ 
    int k = 0; /* Line 3 */
} 
public class Test141 implements Foo141 
{
    public static void main(String args[]) 
    {
        int i; 
        Test141 test141 = new Test141(); 
        i = test141.k; /* Line 11 */
        i = Test141.k; 
        i = Foo141.k; 
    } 
}

Compilation fails.
Compiles and runs ok.
Compiles but throws an Exception at runtime.
Compiles but throws a RuntimeException at runtime.
What will be the output of the program?
String a = "newspaper";
a = a.substring(5,7);
char b = a.charAt(1);
a = a + b;
System.out.println(a);

apa
app
apea
apep
What will be the output of the program?
public class StringRef 
{
    public static void main(String [] args) 
    {
        String s1 = "abc";
        String s2 = "def";
        String s3 = s2;   /* Line 7 */
        s2 = "ghi";
        System.out.println(s1 + s2 + s3);
    }
}

abcdefghi
abcdefdef
abcghidef
abcghighi
What will be the output of the program?
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); 
    } 
}

java
javac
javajavac
Compile error
What will be the output of the program?
class Tree { } 
class Pine extends Tree { } 
class Oak extends Tree { } 
public class Forest1 
{ 
    public static void main (String [] args)
    { 
        Tree tree = new Pine(); 
        if( tree instanceof Pine ) 
            System.out.println ("Pine"); 
        else if( tree instanceof Tree ) 
            System.out.println ("Tree"); 
        else if( tree instanceof Oak ) 
            System.out.println ( "Oak" ); 
        else 
            System.out.println ("Oops "); 
    } 
}

Pine
Tree
Forest
Oops
What will be the output of the program?
String d = "bookkeeper";
d.substring(1,7);
d = "w" + d;
d.append("woo");  /* Line 4 */
System.out.println(d);

wookkeewoo
wbookkeeper
wbookkeewoo
Compilation fails.
What will be the output of the program?

String a = "ABCD"; 
String b = a.toLowerCase(); 
b.replace('a','d'); 
b.replace('b','c'); 
System.out.println(b);

abcd
ABCD
dccd
dcba
What will be the output of the program?
public class ExamQuestion6 
{
    static int x; 
    boolean catch()
    {
        x++; 
        return true; 
    } 
    public static void main(String[] args)
    {
        x=0; 
        if ((catch() | catch()) || catch()) 
            x++; 
        System.out.println(x); 
    } 
}

1
2
3
Compilation Fails
What will be the output of the program?
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(); 
    } 
}

ACCBAD
ABBCAD
CDDACB
Indeterminate output
What will be the output of the program?
String s = "hello"; 
Object o = s; 
if( o.equals(s) )
{
    System.out.println("A"); 
} 
else
{
    System.out.println("B"); 
} 
if( s.equals(o) )
{
    System.out.println("C"); 
} 
else
{ 
    System.out.println("D"); 
}
  1. A
  2. B
  3. C
  4. D

1 and 3
2 and 4
3 and 4
1 and 2
What will be the output of the program (in jdk1.6 or above)?
public class BoolTest 
{
    public static void main(String [] args) 
    {
        Boolean b1 = new Boolean("false");
        boolean b2;
        b2 = b1.booleanValue();
        if (!b2) 
        {
            b2 = true;
            System.out.print("x ");
        }
        if (b1 & b2) /* Line 13 */
        {
            System.out.print("y ");
        }
        System.out.println("z");
    }
}

z
x z
y z
Compilation fails.