when asub class inherits a super class and overrides a
public method of super class in sub class(public method in
super class).
why these methods needs to be public in sub class.
(otherwise compile time error).
Question 6 [9]
6.1 In what situations (in general) would you use a
TreeMap? (3)
6.2 In what situations (in general) would you use a HashSet
to store a collection of
values?
22
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.
hi am an engineering student and my next plan is for ms in
either in us or australia i got my passport but i dont know
anything bout visa can u give brief idea
1)How to get prepared for visa and
2)How to apply for top universities and
3)How to pay the fee and so on
These all are basic questions plz give me a clear idea
75
What happens to the Exception object after handling an
exception?
120
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 7 [8]
Consider the following class and answer the questions below
it:
public class StackWithGuard extends Stack {
public StackWithGuard(int size) {
super(size);
}
synchronized public boolean isEmpty() {
return super.isEmpty();
}
synchronized public boolean isFull() {
return super.isFull();
}
synchronized public int getSize() {
return super.getSize();
}
synchronized public void push(Object obj) {
try {
while (isFull()) {
wait();
}
} catch (InterruptedException e) {}
super.push(obj);
COS2144/102
11
notify();
}
synchronized public Object pop() {
try {
while (isEmpty()) {
wait();
}
} catch (InterruptedException e) {}
Object result = super.pop();
notify();
return result;
}
public static void main(String args[]) {
StackWithGuard stack = new StackWithGuard(5);
new Producer(stack, 15).start();
new Consumer(stack, 15).start();
}
}
Note: The Stack class is provided in the Appendix.
Note also: The following questions all refer to the pop()
method of the StackWithGuard
class given above.
7.1 What does the synchronized keyword ensure for this
method? (2)
7.2 Why is a while loop used to test whether the stack is
empty? In other words, why
wouldn't the following if statement be sufficient?
if (isEmpty()) {
wait();
}
(2)
7.3 Why is the result of popping (provided by the inherited
pop() method) stored in a
temporary variable? In other words, why wouldn't the
following statement be
sufficient?
return super.pop();
(2)
7.4 Why is the while loop placed in a try-catch structure?
(2)
Appendix
The LinkedQueue class:
public class LinkedQueue implements Queue {
private Node first, last;
private int count;
public LinkedQueue() {
first = last = null;
count =0;
}
public int size() {
return count;
}
public boolean isEmpty() {
return (count == 0);
12
}
public void enqueue(Object o) {
Node node = new Node();
node.element = o;
node.next = null;
node.prev = last;
if (last != null){
last.next = node;
}
else {
last = first = node;
}
last = node;
count++;
}
public void dequeue() {
if ((first!= null) & (first.next!=null)) {
first = first.next;
first.prev = null;
count--;
}
else {
first = last = null;
count--;
}
}
public Object front() {
return first;
}
}
class Node {
Object element;
Node next, prev;
}
The Stack class:
public class Stack {
protected Object rep[];
protected int top = -1;
protected int size = 0;
protected int count = 0;
public Stack(int size) {
if (size > 0) {
this.size = size;
rep = new Object[size];
}
}
public boolean isFull() {
return (count == size);
}
public boolean isEmpty() {
return (count == 0);
}
public int getSize() {
return size;
}
public void push(Object e) {
if (e != null && !isFull()) {
COS2144/102
13
top++;
rep[top] = e;
count ++;
}
}
public Object pop() {
Object result = null;
if (!isEmpty()) {
result = rep[top];
top--;
count--;
}
return result;
}
}
27
Write the program numbers into words.For example
2345==two thousand three hundred fourty five
Howto get an object that will perform date & time calculations
then format it for output in some different locales with
different date style.can ne1 tel me the answer of this
question.pls
47
What releases of Java technology are currently available?
What do they contain?
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