What is inner class?what is the use of inner class?where we
create the object for inner class? and inner class can
extend any class or inner class can implement any interface?
53
What is the difference between JDBC 1.0 and JDBC 2.0?
how to run ecllipse with jettyserver for windows
environment using batch file
96
4.1 Supply contracts (in the form of comments specifying
pre- and post conditions)
for the enqueue() method of the LinkedQueue class given in
the Appendix.
(2)
4.2 Let Thing be a class which is capable of cloning
objects, and consider the code
fragment:
Thing thing1 = new Thing(); //(1)
Thing thing2 = thing1; //(2)
Thing thing3 = (Thing) thing1.clone(); //(3)
Explain how the objects thing2 and thing3 differ from each
other after
execution of the statements.
(
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Which of the following is not an isolation level in the JDBC
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)
18
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
How to display names of all components in a Container?
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
EDS (Electronic Data Systems India Pvt Ltd) at Chennai on 16-12-2006.