class A{
some variables;
public void a()throws Excepion1,Exception2{....}
}
class B extends A{
variables...
public void a()throws E2,E3{.....}
}
Qns:
here override of methods occurs or not,ore else wil give
any compilation error or run properly..plz tell me briefly
whts happening with the above codes....
23. Storage space in java is of the form
Stack
Queue
Heap
List
24. What is java code embedded in a web page known as
Applets
Servlets
scriptlets
snippets
25. Which of the following attributes are compulsory with
an <applet> tag?.
code,height & width.
26. What does 'CODEBASE' in an applet tag specify?.
Files absolute path.
what is polymorhism
what is inheritance?
what is Abstract n Interface?
what if two interfaces have same method and a concrete
class is implementing both the
interfaces. Will there be a compilation error?
What are mutable and immutable classes?
How can u make a class mutable?
when will u use dem ...explain with example?
what is overriding and overloading?
what is garbage collection?
what is Thread? how do dey communicate?
what are the different ways of implementing ?
have u used any messaging technologies?
what is synchronization?
what are some additions in java 1.5?
what are generics?
whst is advanced for loop?
what is finally block?
can u have a try in finally? yes!!
can u have a finally in finally?
how do you write junits?
when is a object eligible for garbage collection?explain?
a = null and b has ref to a will b be eligible to be
garbage collected?
sql questions like diff joins? how do dey work?
exception handling?
what is marker interface? what is the need??
Write a java program to find the route that connects
between Red and Green Cells.
General Rules for traversal
1. You can traverse from one cell to another
vertically, horizontally or diagonally.
2. You cannot traverse through Black cells.
3. There should be only one Red and Green cell and at
least one of each should be present. Otherwise the array is
invalid.
4. You cannot revisit a cell that you have already
traversed.
5. The maze need not be in the same as given in the
above example
152
how to write a program for chat function using core java
Which Component subclass is used for drawing and painting?
129
What are parent methods and how can you call them?
194
can any one tell me what is advantage of encapsulation
113
How to connect to a remote database using Applet?
223
How to add and remove nodes in Jtree?
235
The following program reads data (details of students) from
a file named students.txt and
converts it into e-mail addresses. The results are written
to a file named studentemail.txt.
students.txt consists of a number of lines, each containing
the data of a student in colon
delimited format:
Last Name:First Name:Student Number
Each input record is converted to an e-mail address and
written to studentemail.txt in the
following format:
the first character of the last name + the first character
of the first name + the last four digits of
the student number + “@myunisa.ac.za”
import java.io.*;
public class EmailConverter {
public static void main(String[] args) throws IOException {
BufferedReader input = new BufferedReader(new FileReader
("students.txt"));
PrintWriter output = new PrintWriter(new FileWriter
("studentemail.txt"));
String line = input.readLine();
while (line != null) {
// Extract the information for each student
String[] items = line.split(":");
// Generate the email address
String email = "" + items[0].charAt(0) + items[1].charAt(0)
+
items[2].substring(4,8) + "@myunisa.ac.za";
email = email.toLowerCase();
// Output
output.println(email);
line = input.readLine();
}
input.close();
output.close();
}
}
Rewrite the class so that it handles possible errors that
may occur. In particular, it should do the
following:
• It should catch at least three appropriate exceptions
that might occur, and display suitable
messages.
• At this stage, the program will not run correctly if
there is an empty line in the input file.
Change the program so that if an empty line is encountered,
an exception is thrown and the
empty line is ignored. This exception should be handled
with the display of a suitable error
message.
• Before the e-mail address is added to the output file,
check if the student number has 8
digits. If not, throw an InvalidFormatException (which the
program should not handle itself)
21
What is the difference between JDBC 1.0 and JDBC 2.0?
I need some details about an employee. i have only the
employee id in my presentation layer(JSP).I entered that ID
and click "Show Details" Button. Question is how the JSP
pass that id to Controller layer and DAO and what mechanism
we are using to retrive data from DB and how the data
passed to JSP as a Output. Please explain in detail.
Difference between a MenuItem and a CheckboxMenuItem?
196
How to implement a multithreaded applet?
323
There is a Banking application. It has 2 types of account,
Savings and Current. Write a method calculateInterest by
passing an ArrayList of these account objects and calculate
Interest accordingly. Write code for this situation
Question 5 [15]
Consider the following classes, illustrating the Strategy
design pattern:
import java.awt.*;
abstract class Text {
protected TextApplet tA;
protected Text(TextApplet tApplet) {
tA = tApplet;
}
abstract public void draw(Graphics g);
}
class PlainText extends Text {
protected PlainText(TextApplet tApplet) {
super(tApplet);
}
public void draw(Graphics g) {
g.setColor(tA.getColor());
g.setFont(new Font("Sans-serif", Font.PLAIN, 12));
g.drawString(tA.getText(), 20, 20);
}
}
class CodeText extends Text {
protected CodeText(TextApplet tApplet) {
super(tApplet);
}
public void draw(Graphics g) {
g.setColor(tA.getColor());
g.setFont(new Font("Monospaced", Font.PLAIN, 12));
g.drawString(tA.getText(), 20, 20);
}
}
public class TextApplet extends java.applet.Applet {
protected Text text;
protected String textVal;
protected Color color;
public String getText() {
return textVal;
}
public Color getColor() {
return color;
}
public void init() {
textVal = getParameter("text");
String textStyle = getParameter("style");
String textColor = getParameter("color");
if (textStyle == "code")
text = new CodeText(this);
else
text = new PlainText(this);
if (textColor == "red")
color = Color.RED;
else if (textColor == "blue")
color = Color.BLUE;
else
color = Color.BLACK;
}
public void paint(Graphics g) {
text.draw(g);
10
}
}
The Text class is more complicated than it should be (there
is too much coupling between the
Text and TextApplet classes). By getting rid of the
reference to a TextApplet object in the
Text class and setting the colour in the paint() method,
one could turn the Text class into an
interface and simplify the strategy classes considerably.
5.1 Rewrite the Text and PlainText classes to do what is
described above. (6)
5.2 Explain the consequent changes that are necessary to
the TextApplet class. (4)
5.3 Write an additional strategy class called FancyText (to
go with your simplified
strategy classes) to allow fancy text to be displayed for
the value "fancy" provided
for the style parameter. It should use the font Font
("Serif", Font.ITALIC, 12).
(3)
5.4 Explain what changes are necessary to the TextApplet
class for this. (2)
21
How will you serialize a singleton class without violating
singleton pattern?
35
Is there any use of an abstract class which has no methods
and no attributes?
Name the components that are termed to be Heavy-weight
component but available in Light-weight components?
370
Is it safe for adding 10,00,000 records/objects to
HashMap?, i.e is it safe to add millions of objects to
HashMap?
107
Say you want to store the information about a number of
pets in an array. Typical
information that you could store for each pet (where
relevant) would be
• Breed of animal
• Animal's name
• Its birth date
• Its sex
• Whether it has been sterilised or not
• When it is due for its next inoculation
• When it last had its wings clipped
For each type of pet (eg. dog, cat or bird) you would
typically define a class to hold
the relevant data.
Note: You do not need to implement these classes. Just
answer the following
questions.
3.1.1 What would be the advantage of creating a superclass
(eg. Pet) and
declaring an array of Pet objects over simply using an
array of Objects,
storing each of the instances of the different pet classes
(eg. Dog, Cat or
Bird) in it?
3.1.2 Would you define Pet as a class or as an interface?
Why?
(2)
(2)
Did you received any Funny E-Mails from your Friends and like to share with rest of our friends? Yeah!! you can post that stuff 
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