JSharp 2003 Test Answers

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1. You have created the following class to print some numbers:

public class PrintNumber {
         int a;
         int b;
        
         public void basefunt() {
            a = 0;
            b = 0;
            int[] c = { 0 };
            modify(b, c);
                System.out.println("" + a  + b + c[0]);
         }
   
         public void modify(int b, int[] c) {
            a = 1;
            b = 1;
            c[0] = 1;
         }

          public static void main(String args[]) {
            PrintNumber  p = new PrintNumber();
            p.basefunt();
         }
       }

What will be the output?
Answers:
• 000
• 101
• 001
• 110
• 100

2. Which of the following is incorrect with regard to Exceptions?
Answers:
• Catching java.lang.Exception will catch any .NET exceptions
• Catching System.Exception will catch any .NET exceptions
• Catching java.lang.Exception will catch any java exceptions
• Catching System.Exception will catch any java exceptions
3. You have defined an Integer as follows:

int IntPageId = 5;

What would you write for changing it into a String data type?
Answers:
• String strPageId = System.Data.ToString(IntPageId);
• String strPageId = IntPageId.ToString();
• String strPageId = System.Convert.ToString(IntPageId);
• String strPageId = IntPageId;
4. You have defined two classes (as mentioned below) in a java file named "CustomerClass.java" :
class Customer
{
. . .
}

class OldCustomer
{
. . .
}
None of the classes defined above have any static void method. What will happen on compiling the classes on .Net command prompt?
Answers:
• This will give a compilation error saying 'one class must be declared public'
• This will give a compilation error saying 'two non-public classes cannot be declared in one java file'
• This will give a compilation error saying, 'No main method found'
• None of the above
5. You want a component to resize vertically, but not horizontally. How should it be placed?
Answers:
• BorderLayout in the North or South location
• FlowLayout as the first component
• BorderLayout in the East or West location
• BorderLayout in the Center location
• GridLayout
6. Two functions are defined with the same name in a class:

public boolean isGreater(int no1, int no2)
public boolean isGreater(String st1, String st2)

Which of the following concept does this definition represent?
Answers:
• Abstraction
• Overloading
• Overriding
• Encapsulation
7. Which of the following statements is incorrect  with regard to data types?
Answers:
• J# wraps primitive types to Objects behind the scene
• Primitive data types are defined as structures in the system namespace
• Internal handling of primitive data types in J# is exactly the same as in java
8. A Student class extends Person class:
1 class Person
2 {
3 int heightcm;
4
5 Person()
6 this.heightcm=160;  }
7
8 int getHeight()
9 return heightcm; }
10
11 String display()
12 return "Person height is " + heightcm; }
13 }

14 class Student extends Person
15 {
16 int studhtcm;
17 String className()
18 return "Student"; }
19
20 public static void main(String args[])
21 {
22 Person obj = new Student();
23 System.out.println(obj.getHeight());
24 System.out.println(obj.display());
25 System.out.println(obj.className());
26 }
27 }

What will happen on compiling and running the code?
Answers:
• The Program will compile and run successfully.
• The Program will not compile due to an error in line 23
• The Program will not compile due to an error in line 24
• The Program will not compile due to an error in line 25
9. Which of the following statements is incorrect with regard to Java Code?
Answers:
• The java code can be compiled in Netbean/Eclipse as well as in VisualStudio
• Netbean compiles java source to Java byte code whereas Visual Studio compiles it to MSIL
• Both Netbean and Visual Studio produce class files as a result of compilation
• All of the above
10. You created a few classes (as mentioned below) for file manipulation:

public class CopyFile
{        }
class ReadFile
{        }
class WriteFile
{        }

Which of the following is a valid way to name the '.java' file containing the above classes?
Answers:
• ReadFile.java
• WriteFile.java
• FileManupulation.java
• All of the above
11. What will be the output when the following code is compiled and run?

abstract class Search {
  public Search() { }
 
  public abstract void Result();
}

public class SearchMain extends Search {
 
  public SearchMain() { }
 
  public int Result() {
    System.out.println("I am Result()");
    return 1;
  }

  public static void main(String str[]) {
    new SearchMain().Result();
  }   
}
Answers:
• The code will fail to compile
• The code will compile but fails to run
• The code will compile and print "I am Result()"
• The code will compile but does not produce any output
12. You have defined the following methods in one of the java classes:

1        void setId(int newId)
2        private void manageRecord(int RecordNo)
3        protected void delete(int recordNo)
4        boolean isValidRecord(int recordNo)

Which of the following methods is incorrect for a class that extends above class?
Answers:
• public void setId(int newId)
• void manageRecord(int RecordNo)
• void delete(int recordNo)
• protected boolean isValidRecord(int recordNo)
13. You have compiled a java class named "DirReader.java" using .Net command prompt. Which of the following commands helps you run it from the same window?
Answers:
• >java DirReader
• >java DirReader.java
• >vj DirReader
• >DirReader
14. You have written a java class file named "CustomerManager.java." Which of the following commands helps you compile it on .Net Command prompt?
Answers:
• javax CustomerManager.java
• java CustomerManager.java
• jsharp CustomerManager.java
• vjc CustomerManager.java
15. What will be the output of the following program?

public class Prnt
{
   public static void main(String args[])
   {
       System.out.println(11 ^ 2);
   }
}
Answers:
• 10
• 9
• 11
• 13
• 121
16. What will be the output when myMethod() is executed?

class MyPoint { 

  void myMethod() { 
     int x, y;
     x = 5; y = 3;
     System.out.print( " ( " + x + ", " + y + " ) " );
     switchCoords( x, y );
     System.out.print( " ( " + x + ", " + y + " ) " );
  }

  void switchCoords( int x, int y ) { 
     int temp;
     temp = x;
     x = y;
     y = temp;
     System.out.print( " ( " + x + ", " + y + " ) " );
  }
}
Answers:
• (5, 3) (5, 3) (5, 3)
• (5, 3) (3, 5) (3, 5)
• (5, 3) (3, 5) (5, 3)
• No output will be printed
17. You have a simple java class named "Record":

public class Record
{
protected void readRecord(int newId) throws Exception,IOException{}
protected void insertRec(int recNo) throws FileNotFoundException,IOException{}
protected void deleteRecord(int recordNo) throws EOFException{}
protected boolean isValidRecord(int recordNo) throws Exception{return true;}
}

Which of the following method declarations will not be legitimate for the child class of "Record" class?
Answers:
• protected void readRecord(int newId) throws IOException
• protected void insertRec(int recNo) throws Exception
• public void deleteRecord(int recordNo) throws EOFException
• public boolean isValidRecord(int recordNo) throws EOFException
18. Which of the following statements is correct with regard to Final and Abstract?
Answers:
• An abstract class cannot have final methods
• An abstract class cannot have non abstract methods
• A final class cannot have abstract methods
• A final class cannot have final methods
19. Given below is the definition of two classes in "Maruti.java":
public class Automobile
{        Automobile(int i) {}        }

class Maruti extends Automobile
{
        public Maruti()
        {        System.out.println("In Maruti()");        }

        public static void main(String str[])
        {        new Maruti();                                }   
}

What will happen when this code is compiled and run?
Answers:
• The code will compile but throws an exception when it is run
• The code will compile and does not produce any output when it is run
• The code will fail to compile
• None of the above
20. Which of the following classes does not generate action events?
Answers:
• Choice
• MenuItem
• List
• Checkbox
21. Consider the following program:

import java.util.*;
public class ListColl {
   public static void main(String str[]) {   
     List l = new ArrayList();
     l.add("1");
     l.add("2");
     l.add(1,"3");
     List l2 = new LinkedList(l);
     l.addAll(l2);

     System.out.println(l);   
   }
}

Which of the following sequences will be printed when the above program is run?
Answers:
• [1, 3, 2, 1, 1, 2]
• [1, 3, 1, 1, 3, 2]
• [1, 1, 2, 1, 3, 2]
• [1, 3, 2, 1, 3, 2]
22. What will be returned by the length()method of File class?
Answers:
• The number of characters in the file
• The number of bytes in the file
• The number of lines in the file
• None of the above
23. You created the 'Msg' class as follows:
class Msg {
        Msg() {
            String str1 = "Health";
            String str2 = "is";
            String str3 = "Wealth";

            System.out.println(str1.concat(str2));
            str1.concat(str2);
            System.out.println(str1.concat(str3));                   
        }

        public static void main(String str[]) {
            new Msg();
        }
}

What will happen on compiling and running the code?
Answers:
• This code will fail to compile because arrayIndexOutOfBound exception is not caught
• It will print Healthis on the first line followed by HealthWealth on the second line
• It will print Healthis on the first line followed by HealthisWealth on the second line
• It will print Healthis on the first line followed by HealthisHealthWealth on the second line
24. A class named MyLoop is defined as follows:

public class MyLoop
{
           public static void main(String args[])
        {
               int counter = 0;
               lbl1: for (int i=10; i<0; i--)
                {
                  int j = 0;
                   lbl2:  while (j < 10)
                        {
                               if (j > i) break lbl2;
                                if (i == j)
                                 {
                           counter++;
                           continue lbl1;
                                }
                           }
                           counter--;
               }
       System.out.println(counter);
           }
}

What will happen when you try to compile and run the program?
Answers:
• The program will fail to compile
• The program will compile and produce no output
• The program will print 0 as output
• The program will print 10 as output
25. You have defined a static method to divide two integers:

1 public static int divide(int a,int b) throws Exception
2 {
3 if(b==0)
4 throw new Exception("Invalid Value for denominator");
5 else
6 return (a/b);
7 }

Which of the following statements is correct?
Answers:
• The method syntax is correct
• The general Exception cannot be specified with parameter (line 4)
• In the line 4, the word 'throw' should be replaced with 'throws'
• A static method can be throw not as throw Exceptions
26. What will be the output when the following code is compiled and run?

class Equates {
     Equates() {
       int a,b,c;
       a = b = c = 20;
       System.out.println(a);
     }
     public static void main(String str[]) {
       new Equates();
     }
}
Answers:
• The code will fail to compile
• 20 is printed
• Nothing is printed
• True is printed
27. The classes Zen and Matiz are as follows:

class Zen {
    int x = 10;
}

class Matiz {
     Matiz() {
       Zen z1 = new Zen();
       Zen z2 = new Zen();
     
       update(z1);
       update(z2);
       z1 = z2;
       update(z1);
       update(z2);
     }
   
     private void update(Zen z) {
        z.x = 20;
        System.out.println(z.x);
     }

     public static void main(String str[]) {
       new Matiz();
     }
}

What will be the result obtained on compiling and running the Matiz class?
Answers:
• The code will fail to compile
• 10 10 10 10
• 20 20 20 20
• 10 20 10 20
28. You need to create a class that associates a set of keys with a set of values. Which of these interfaces is most appropriate?
Answers:
• Collection
• Set
• Map
• SortedSet
29. In the following code, val is an Integer variable:

if( val > 4 ) { 
  System.out.println( "Test A" );
}else if( val > 9 ) { 
  System.out.println( "Test B" );
}else
  System.out.println( "Test C" );

Which of the following values of 'val' will print 'Test C'?
Answers:
• val < 4
• val between 4 and 9
• val > 9
• No values for val will result in "Test C" being printed
30. Consider the following class:

public class Intro {
        static int a;
        int b;
   
        public Intro() {
            int c;
            c = a;
            a++;
            b += c;
        }

        public void Intro() {
           int c;
            c = a;
            a++;
            b += c;
        }

        public static void main(String args[]) {
           new Intro();
        }
  }

What will happen on compiling and running this class?
Answers:
• The code will fail to compile because there are two constructors with the same names and parameters
• The code will fail to compile because the constructor is trying to access a static variable
• The code will compile but gives a runtime error
• The code will compile and runs successfully
31. Which of the following Classes contains a method to create a directory?
Answers:
• File
• DataOutput
• Directory
• FileDescriptor
• FileOutputStream
32. Which of the following statements is correct with regard to J#?
Answers:
• All the J# data types are derived from java.lang.Object
• The java.lang.Object is a superclass of System.Object
• The java.lang.Object is an alias for System.Object
• The ObjectImpl package provides functionality for all the methods belonging to java.lang.Object
33. Consider the following class:

import java.util.*;
public class Coll
{
   public static void main(String str[])
   { 
     List l = new ArrayList();
     l.add("1");
     l.add("2");
     l.add(1,"3");

l2 = new LinkedList(l);
     l.addAll(l2);

     System.out.println(l);   
   }
}

Which of the following sequences will be printed on running this class?
Answers:
• [1, 3, 2, 1, 1, 2]
• [1, 3, 1, 1, 3, 2]
• [1, 1, 2, 1, 3, 2]
• [1, 3, 2, 1, 3, 2]
34. What will be the output when the following code is compiled and run?

class Num {
     Num() {
       int k = 1;
       int i = ++k + k++ + + k;
       System.out.println(i);
     }
     public static void main(String str[]) {
       new Num();
     }
}
Answers:
• The code will fail to compile
• 8 is printed
• 9 is printed
• 7 is printed
35. What is wrong with the following method?

public void manageCalc()
{
   try {
           compute();
       } finally {
           release();
       } catch (MyException e) {}
   }
}
Answers:
• There is no error in the code
• The block 'finally' should come after the block 'catch'
• An empty catch block is not allowed
• None of the above
36. Two classes are defined as follows:

class Category {}
class Document extends Category {}
class Legal extends Document {}

You initialized the class Legal like this:
Legal legl = new Legal();

What is the sequence of call to the given classes?
Answers:
• It calls Legal(),Document(), and Category()
• It calls Legal(),Category(), and Document()
• It calls Category(),Document(), and Legal()
• It calls Category(),Legal(), and Document()
37. The Tracer and Viewer classes are as follows:
class Tracer {
  public static int traceNo = 10;
}

class Viewer {

     Viewer() {
       Tracer t1 = new Tracer();
       Tracer t2 = new Tracer();
     
       update(t1);
       update(t2);
     }
   
     private void update(Tracer t) {
        t.traceNo = t.traceNo + 1;
        System.out.println(t.traceNo);
     }

     public static void main(String str[]) {
       new Viewer();
     }
}

What will be the result obtained on compiling and running the viewer on .net command prompt?
Answers:
• The code will fail to compile
• 11 12
• 11 11
• 12 12
38. Consider the following classes:
class Model
{
public int modelNo;

Model(int modelNum)
        {        modelNo=modelNum;        }

public int getModel()
        {         return modelNo;        }
}

public class Item extends Model
{
Item() {}

public static void main(String args[])
        {        Item i = new Item();        }
}
What will happen on compiling and running the above classes?
Answers:
• The code will compile and run successfully
• The code will not compile as the constructor Item (int modelNo) is missing in the Item class
• The code will not compile as the call super (ModelNumber) is missing in Item()
• The code will compile but gives runtime error
39. Which of the following statements is incorrect with regard to interfaces?
Answers:
• A class can implement multiple interfaces
• An abstract class cannot extend multiple interfaces
• An interface can extend multiple interfaces
• Methods with same name, arguments, and sequence can exist in the interfaces implemented by a class
40. Which of the following methods will cause a thread to stop?
Answers:
• Calling interrupt() method of the thread
• Calling sleep() method on thread
• Conclusion of execution of the run() method
• None of the above
41. Which of the following is correct with regard to Net J#?
Answers:
• It supports sun java up to JDK 1.1.5
• It supports sun java up to JDK 1.1.4
• It supports sun java up to JDK 1.1.3
• It supports sun java enterprise edition and standard edition
42. For a J# project in Visual Studio .Net, the files can be a mixture of .jsl or .java extensions.
Answers:
• True
• False
43. Which of the following is not a correct way of getting 'sin' value?
Answers:
• Math m = null; double val = m.sin(25);
• double val = Math.sin(25);
• Math m = new Math(); double val = m.sin(25);
44. Which of the following visibility modes is not defined in J#?
Answers:
• protected
• private
• package
• default
45. Visual J# runs on .Net framework.
Answers:
• True
• False
46. Which of the following helps you get a double value from a String object named "StrValue?"
Answers:
• (System.Double)(System.GetDouble(StrValue))
• (System.Double)(System.ParseDouble(StrValue))
• (System.Double)(System.Double.Parse(StrValue))
• System.Double.Parse(StrValue)
47. What will be written to the standard output when the following program is run?

public class Message
{
   public static void main(String args[])
   {
       String msg = "GoodDay";
       System.out.println(msg.substring(3, 4));
   }
}
Answers:
• o
• odD
• d
• dDay
48. How is applet loading speed increased with J# 1.1?
Answers:
• By using a special algorithm to increase the download speed
• By using CAB files to download the applet
• By using ZIP files to reduce the size for download
• All of the above
49. Which of the following are supported by J#?
Answers:
• Windows Forms
• ASP.NET Web Forms and Mobile Web Forms
• XML Web services
• Cross-language integration
• All of the above