UpWork (oDesk) & Elance Java v3 Test Question & Answers

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Ques : What is the result of an attempt to compile and run the given program?

public class Test107 {

        public static void main(String[] args) {

                System.out.println(test());

        }

        private static int test() {

                return (true ? null : 0);

        }

}

Ans  : It compiles, but throws NullPointerException at run-time.

Ques : What is the output of the given program?

public class Test93 {
        private int x = 0;

        public static void main(String[] args) {
                new Test93().test();
        }

        private int f(int x) { return ++x; }
        private int g(int y) { return x++; }

        private void test() {
                System.out.print( f(x)==f(x) ? "f" : "#" );
                System.out.print( g(x)==g(x) ? "g" : "#" );
        }
}
Ans  : f#

Ques : Which design pattern reduces network traffic by acting as a caching proxy of a remote object?
Ans  : Value Object

Ques : What is the output of the given program?

public class Test89 {
        public static void main(String[] args) {
                T x = new T("X", null); x.start();
                T y = new T("Y", x); y.start();
                T z = new T("Z", y); z.start();
        }
}
class T extends Thread {
        private Thread predecessor;
        private String name;
        public T(String name, Thread predecessor) {
                this.predecessor = predecessor;
                this.name = name;
        }
        public void run() {
                try {
                        Thread.sleep((int)(Math.random()*89));
                        System.out.print(name);
                } catch (InterruptedException ie) {
                        ie.printStackTrace();
                }
        }
}
Ans  : any of the following: XYZ, XZY, YXZ, YZX, ZXY, ZYX

Ques : Assuming that val has been defined as an int for the code below, which values of val will result in "Test C" being printed?

if( val > 4 ) {

 System.out.println("Test A");

} else if( val > 9 ) {

 System.out.println("Test B");

} else

 System.out.println("Test C");
Ans  : val between 0 and 4

Ques : How many objects are created by the following code?


Object a, b, c, d, e;

e = new Object ();

b = a = e;

e = new Object ();
Ans  : 2

Ques : Which of the following is the correct syntax for creating a Session object?
Ans  :  HttpSession ses=request.getSession()

Ques : Which statement is true about the given code?

public class Test78 {
        public static void main(String[] args) throws Exception {
                new JBean().setHeight(1).setWidth(2).setDepth(3).setDensity(9);
        }
}
class JBean {
        private int height, width, depth, density;
        public JBean setHeight  (int h) { this.height  = h; return this; }
        public JBean setWidth   (int w) { this.width   = w; return this; }
        public JBean setDepth   (int d) { this.depth   = d; return this; }
        public JBean setDensity (int d) { this.density = d; return this; }
}
Ans  : The code compiles and runs.

Ques : X.509 version 3 specifies which of the following?
Ans  :  A format and content for digital certificates.

Ques : How many objects are created in the given code?

Object x, y, z;
x = new Object();
y = new Object();
Ans  : 2

Ques : How does the set collection deal with duplicate elements?
Ans  : The add method returns false if you attempt to add an element with a duplicate value.

Ques : Conventionally, which directory do servlet class files get placed on?
Ans  :  WEB-INF\classes

Ques : Which is a proper way to declare and throw exception of class XYException?
Ans  : class XYException extends Exception {} ... throw new XYException();

Ques : Which of the following is a well-known HTTP port?
Ans  : 80

Ques : What is the output of the given program?

public class Test89 {
        public static void main(String[] args) {
                T x = new T(""X"", null); x.start();
                T y = new T(""Y"", x);    y.start();
                T z = new T(""Z"", y);    z.start();
        }
}
class T extends Thread {
        private Thread predecessor;
        private String name;
        public T(String name, Thread predecessor) {
                this.predecessor = predecessor;
                this.name = name;
        }
        public void run() {
                try {
                        Thread.sleep((int)(Math.random()*89));
                        System.out.print(name);
                } catch (InterruptedException ie) {
                        ie.printStackTrace();
                }
        }
}
Ans  : Any of the following: XYZ, XZY, YXZ, YZX, ZXY, ZYX

Ques :  Which of the following code snippets will take transform input string "2012/06/05"  to output string "05 - 06 - 2012"?
Ans  : String dateString = "2012/06/05"; Date date = new SimpleDateFormat("yyyy/MM/dd").parse(dateString); SimpleDateFormat sdf = new SimpleDateFormat("dd - MM - yyyy"); System.out.println(sdf.format(date));

Ques : Which statement is true regarding ServletContext Initialization Parameters in the deployment descriptor?
Ans  : They are accessible by all servlets in a given web application.

Ques : Which of the following is the correct syntax for suggesting that the JVM perform garbage collection?
Ans  : System.gc();

Ques : Why can't a Graphics object be created using the following statement?

Graphics g = new Graphics();
Ans  :  The Graphics class is an abstract class.

Ques : What is the output of the given program?

public class Test97 {
        public static void main(String[] args) {
                int[][] a = new int[2][2];
                System.out.println(a.length);
        }
}
Ans  : 2

Ques : Which of the following interfaces makes it possible for Java to save an object to a file and turn it into a data stream?
Ans  :  java.io.Serializable

Ques : How many objects are created in the given code?

Object x, y, z;
x = new Object();
y = new Object()
Ans  : 2

Ques : Consider the following code:

public static void main(String bicycle[])
{
        System.out.println(bicycle[0]);
}

What would be the result if "java TwoTyre one two" is entered in the command line?
Ans  : one

Ques : What is the term to describe a situation where two or more threads are blocked forever, waiting for each other?
Ans  : deadlock

Ques : SQLException has a feature of chaining - identify the right code to execute the same from the following options:
Ans  :  catch(SQLException e) { out.println(e.getMessage()); while((e=e.getNextException())!=null) { out.println(e.getMessage()); } }

Ques : Which statements are true regarding ServletContext Init Parameters in the deployment descriptor?
Ans  :  They are set at deployment-time and can be updated at run-time.

Ques : Which of the following methods are members of the Vector class and allow you to input a new element?
Ans  : addElement

Ques : In which class is the notify method defined?
Ans  : Object

Ques : The principal finder method that must be implemented by every entity bean class is:
Ans  :  findByPrimaryKey()

Ques : Which option lists Java access modifiers in the right order from the most permissive to the most restrictive?
Ans  : public, protected, []no modifier/default/package[], private

Ques : What should be the replacement of "//ABC" in the following code?

class Krit
{
    String str= new String("OOPS !!! JAVA");
    public void KritMethod(final int iArgs)
    {
      int iOne;
      class Bicycle
      {
        public void sayHello()
        {
          //ABC
        }
      }
    }
    public void Method2()
    {
      int iTwo;
    }
}
Ans  : System.out.print(str);

Ques : What is the output of the given program?

public class Test118 extends _Test118 {
        {
                System.out.print("_INIT");
        }
        static {
                System.out.print("_STATIC");
        }
        Test118() {
                System.out.print("_CONST");
        }
        public static void main(String[] args) {
                System.out.print("_MAIN");
                new Test118();
        }
}
class _Test118 {
        _Test118() {
                System.out.print("_BASE");
        }
}
Ans  :  _STATIC_MAIN_BASE_INIT_CONST

Ques : What will be the output, if the following program is run?
public class Test8 {
    public static void main(String[] args) {
        System.out.println(Math.sqrt(-4));
    }
}
Ans  : NaN

Ques : What will be the output of this program?

public class Test {

 public static void main(String args[]) {

  int a, b;
  a = 2;
  b = 0;
  System.out.println(g(a, new int[] { b }));
 }

 public static int g(int a, int b[]) {

  b[0] = 2 * a;
  return b[0];
 }
}
Ans  : 4

Ques : There are three classes named A, B, and C. The class B is derived from class A and class C is derived from B. Which of the following relations are correct for the given classes?
Ans  : Any instance of B is an instance of A.

Ques : What is the output of the given console application?

public class Test19 {
        public static void main(String[] args) {
                final int X = 9;
                int[][] a = {{5, 4, 3}, {9, 7, 2}, {1, 6, 8}};
                for (int i=0; i<3 b="" i="">
                        for (int j=0; j<3 b="" j="">
                                if (a[i][j] == X) break;
                                System.out.print(a[i][j] + "" "");
                        }
                }
        }
}
Ans  : 5 4 3 1 6 8

Ques : Which of the following statements is true?
Ans  :  public interface RemoteTrain extends java.rmi.Remote

Ques : The JDK comes with a special program that generates skeleton and stub objects that is known as:
Ans  : rmic

Ques :  Which of these interfaces is the most applicable when creating a class that associates a set of keys with a set of values?
Ans  : Map

Ques : Choose all valid forms of the argument list for the FileOutputStream constructor shown below:
Ans  :  FileOutputStream( File f )

Ques : Which of the following methods should be invoked by the container to get a bean back to its working state?
Ans  : EJBActivate()

Ques :  Select all true statements:
Ans  : An abstract class can have non-abstract methods.

Ques :  Which option could be used to see additional warnings about code that mixes legacy code with code that uses generics?
Ans  :  -Xlint:unchecked

Ques : Assuming the servlet method for handling HTTPGET requests is doGet(HttpServletRequest req, HTTPServletResponse res), how can the request parameter in that servlet be retrieved?
Ans  :  String value=req.getParameter("product");

Ques : Which of these is not an event listener adapter defined in the java.awt.event package?
Ans  : ActionAdapter

Ques : What would be the result of compiling and running the following code class?

public class Test {

 public static void main(String args[]) {

  Test t = new Test();
  t.start();
 }

 public void start() {

  int i = 2;
  int j = 3;
  int x = i & j;
  System.out.println(x);
 }
}
Ans  :  The code will compile and print 2.

Ques : Which of the following are the methods of the Thread class?
Ans  :  yield()

Ques :  What protocol is used by the DatagramSocket class?
Ans  : UDP

Ques : Which statements are true? Select all true statements.
Ans  : A method can be declared synchronized.

Ques : Which exception must a setter of a constrained JavaBean property throw to prevent the property value from changing?
Ans  :  PropertyVetoException

Ques : What will be the output when this code is compiled and run?
public class Test {

    public Test() {

        Bar b = new Bar();
        Bar b1 = new Bar();
        update(b);
        update(b1);
        b1 = b;
        update(b);
        update(b1);
    }

    private void update(Bar bar) {

        bar.x = 20;
        System.out.println(bar.x);
    }

    public static void main(String args[]) {

        new Test();
    }

    private class Bar {

        int x = 10;
    }
}
Ans  : 20 20 20 20

Ques :  Which of the following methods can be used for reporting a warning on a Connection object, Statement object & ResultSet object?
Ans  : getWarnings()

Ques : Which of the following are valid ways to define a thread in Java?
Ans  :  Create a subclass of java.lang.Thread class

Ques : JDBC is based on:
Ans  : X/Open CLI (Call Level Interface)

Ques : Which of the following statements regarding abstract classes are true?
Ans  :  The abstract class may have method implementation.

Ques :  Which of the following is the name of the cookie used by Servlet Containers to maintain session information?
Ans  : JSESSIONID

Ques : Which method is called by the servlet container just after the servlet is removed from service?
Ans  : public void destroy() {// code...}

Ques : The transaction attribute of a bean is set to 'TX_REQUIRES_NEW.' What can be inferred about its behavior?
Ans  : The bean manages its own transaction.

Ques : What is the output of the given program?

public class Test106 {
        public static void main(String[] args) {
                Integer x = 0;
                Integer y = 0;
                Integer a = 1000;
                Integer b = 1000;
                System.out.println( (a==b) + "; " + (x==y) );
        }
}
Ans  :  false; true

Which of the following is the correct way to complete the code snippet above?
Ques : Which of the following transaction modes are supported by Enterprise Java Beans?
Ans  : All of the above

Ques :What is the output of the given program?

public class Test120 extends _Test120 {
        {
                System.out.print("_INIT");
        }
        static {
                System.out.print("_STATIC");
        }
        Test120() {
                System.out.print("_CONST");
        }
        public static void main(String[] args) {
                System.out.print("_MAIN");
                new Test120();
        }
}
class _Test120 {
        {
                System.out.print("_BIN");
        }
        static {
                System.out.print("_START");
        }
        _Test120() {
                System.out.print("_BASE");
        }
}
Ans  : _START_STATIC_MAIN_BIN_BASE_INIT_CONST

Ques :  Which distributed object technology is most appropriate for systems that consist entirely of Java objects?
Ans  : RMI

Ques : The following code was written to save a handle to an EJBObject named 'bookEJBObject' for an online book shop:

javax.ejb.Handle bookHandle = _____________;

ObjectOutputStream stream = new ObjectOutputStream(newFileOutputStream(fileName));
stream.writeObject(bookHandle);
stream.close();

Which of the following methods should be filled in the blank?
Ans  : bookEJBObject.getHandle()

Ques : Which sequence will be printed when the following program is run?

import java.util.*;

public class Test {

 public static void main(String str[]) {

  List l = new ArrayList();
  l.add(''1'');
  l.add(''2'');
  l.add(1,''3'');
  System.out.println(l);
 }
}
Ans  : [1, 3, 2]

Ques : Which of the following JDBC methods is used to retrieve large binary objects?
Ans  : getBinaryStream()

Ques : What is the output of the given program?

public class Test129 {
        public static void main(String[] args) {
                A a = new A2();
                B b = new B2();
                System.out.println(a.a + "" + b.b);
        }
}
class A { int a = 1; }
class A2 extends A { int a = 2; }
class B { public int b = 1; }
class B2 extends B { public int b = 2; }
Ans  :  11

Ques : hat exception is thrown by this code, if arr[j]>arr[j+1]:

public static  void main(String[] args) {
    int []arr={12,23,43,34,3,6,7,1,9,6};
        {
              int temp;
              for (int i=0;i
              {
                for (int j=0;j
                {
                  if (arr[j]>arr[j+1])
                 {
                     temp=arr[j];
                     arr[j+1]=arr[j];
                     arr[j+1]=temp;
                  }
                }
              }
            }
        for(int i=0; i
         {
             System.out.print(arr[i] + " ");
         }
    }
Ans  : ArrayIndexOutOfBoundException

Ques : What is the output of the given console application?

public class Test31 {
        public static void main(String[] args) {
                test();
        }
        public static void test() {
                try {
                        System.out.print("-try");
                        return;
                } catch (Exception e) {
                        System.out.print("-catch");
                } finally {
                        System.out.print("-finally");
                }
        }
}
Ans  :  -try-finally

Ques : Which of these interfaces are used by implementations of models for JTable?
Ans  : TableModel

Ques : Which of the following require explicit try/catch exception handling by the programmer?
Ans  :  Attempting to open a network socket

Ques :  Which of the following statements is true of the HashMap class?
Ans  :  It stores information as key/value pairs.

Ques : Which distributed object technology is most appropriate for systems that consist of objects written in different languages and that execute on different operating system platforms?
Ans  :   CORBA

Ques : What is the output of the given code?

public class Test15 {
        public static void main(String[] args) {
                VO a = new VO(2);
                VO b = new VO(3);
                swapONE(a, b);
                print(a, b);
                swapTWO(a, b);
                print(a, b);
        }

        private static void print(VO a, VO b) {
                System.out.print(a.toString() + b.toString());
        }

        public static void swapONE(VO a, VO b) {
                VO tmp = a;
                a = b;
                b = tmp;
        }
        public static void swapTWO(VO a, VO b) {
                int tmp = a.x;
                a.x = b.x;
                b.x = tmp;
        }
}

class VO {
        public int x;
        public VO(int x) {
                this.x = x;
        }
        public String toString() {
                return String.valueOf(x);
        }    
}
Ans  : 2332

Ques : What would happen on trying to compile and run the following code?

class House {

 public final void MaintainMethod() {
  System.out.println("MaintainMethod");
 }
}

public class Building extends House {

 public static void main(String argv[]) {
  House h = new House();
  h.MaintainMethod();
 }
}
Ans  : Successful compilation and output of "MaintainMethod" at run time.

Ques :  Which of the following code snippets will generate five random numbers between 0 and 200?
Ans  : Random r = new Random(); for (int i = 0; i < 5; i++) { System.out.println(r.nextInt(200)); }

Ques : What will be the output when this code is compiled and run?

public class Test {

 public Test() {

  Bar b = new Bar();
  Bar b1 = new Bar();
  update(b);
  update(b1);
  b1 = b;
  update(b);
  update(b1);
 }

 private void update(Bar bar) {

  bar.x = 20;
  System.out.println(bar.x);
 }

 public static void main(String args[]) {

  new Test();
 }

 private class Bar {

  int x = 10;
 }
}
Ans  : 20 20 20 20

Ques : Which class contains a method to create a directory?
Ans  : File

Ques : What is the output of the given program?

public class Test130 {
        public static void main(String[] args) {
                A a = new A2();
                B b = new B2();
                System.out.println(a.a + """" + b.b());
        }
}
class A {
        public int a = 1;
}
class A2 extends A {
        public int a = 2;
}
class B {
        public int b() { return 1; }
}
class B2 extends B {
        public int b() { return 2; }
}
Ans  : 12

Ques : Select all correct statements:
Ans  : Vector is synchronized, ArrayList is not synchronized

Ques : Which of the following is false?
Ans  : A while loop can be used because next () & previous () methods return -1 beyond the resultset.

Ques : Consider the following code:

public class Jam {

    public void apple(int i, String s) {
    }

    //ABC

}

Choose possible valid code replacements of "//ABC" among the choices:
Ans  :  public void apple(String s, int i) {}

Ques :  RMI allows remote communication between:
Ans  :  Java and Java

Ques : As part of the type erasure process, when compiling a class or interface that extends a parameterized class or implements a parameterized interface, the compiler may need to create a synthetic method, called a _________.
Ans  :  bridge method

Ques :  What will be the output of the following code?
public class MyTest {

    public static void main(String[] args) {
        for (int i=0; i > 10; i+=2) {
            System.out.println(i);
        }
    }
}

Ans  : Nothing will be printed


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