public class Ball {
private int a=show();
int b;
Ball()
{
b=20;
}
public static void main(String args[])throws Exception {
System.out.println(new Ball().a);
}
private int show()
{System.out.println(b);
return b;
}
}
I wanted to know when are the objects created ? when are they initialized? and how is show() getting called without any reference or "this" ?
From the tutorial:instance variables can be declared in class level before or after use.But the code below does not compile. Why?
Java Code:
public class MainApp {
i=5;
public static void main(String[] args) {
System.out.println("Hello World");
}
int i;
} mh_sh_highlight_all('java');
One of the random number generators in Java extract the higher-order bits of the random number in order to get a longer period.
I'm not sure if I understand how this is done. Suppose that the random number r = 0000 1100 1000 1101. If we extract the 16 most significant bits from r; is the new number r = 0000 1100 or r = 0000 1100 0000 0000?
Any link to the accurate explanation of binary trees in java?
View Replies View RelatedThis is what I have to do:Write a program that takes a string of someone's name and prints it out last name first. Your program must use pointers, not array subscripts. You may use the available string manipulation functions if you find an opportunity.
Example:
"George Washington"
"Washington, George"
I am not sure how to reverse the name, I have been looking in my textbook and online and cannot figure it out. This is what I have put together so far, it does not run. At the end it says unnecessary return value.
import java.util.*;
import java.util.Scanner;
public class Test {
public static void main ( String [] args ) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter name: ");
String name = sc.nextLine();
String lastname = "";
String firstname = "";
for(int i = 0; i < name.length(); i++) {
if(name.charAt(i) == ' ')
I am just learning java now i have a problem where i have to run a test order on my internalOrder class from the orderTester class and i,m not sure how to do this ?
This is the code i have for my order class:
public static void testCase8(){
orders ords = new orders ("Pen", 8, -0.5);
System.out.println("Test Case 8:" + "
" + ords.getOrderDetails());
[Code] ....
This is the code for my Internal class
public final static double DISCOUNT = 0.4;
public InternalOrder(String productName,int quantity ){
super(productName, quantity,DISCOUNT);
}
public void printInternalReport(){
System.out.println("Printing internal report ...");
}
Now my orderTest class is passed though orders class if you need that code i will put it up...
I think the following code should trigger a compiler error.
public final class IPoint3D {
private double x;
private double y;
private double z;
public IPoint3D(double x, double y, double z)
[Code] .....
I have a problem where i have to run a test order on my internalOrder class from the orderTester class and I am not sure how to do this. This is the code i have for my orderTester class:
public static void testCase8(){
orders ords = new orders ("Pen", 8, -0.5);
System.out.println("Test Case 8:" + "
" + ords.getOrderDetails());
[Code] ....
this is the code for my Internal class
public InternalOrder(String productName,int quantity ){
super(productName, quantity,DISCOUNT); }
public void printInternalReport(){
System.out.println("Printing internal report ...");
}
Now my orderTest class is passed though orders class and intrenalOrder class if you need that code i will put it up.
Being new to java I am a bit lost as to why my session attribute for this banking app wont add the deposits to the session var... it just keeps going back to the amount I set it to originally - so if I set the beginning balance to 3000 then deposit 100 it becomes 3100, but if I then try deposit another amount eg. a extra 200 it becomes 3200 not 3300 like it should be !!
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.net.*;
import java.text.DecimalFormat;
public class SessionBank extends HttpServlet
[Code] .....
I have come across some code where the method signature is like,
public methodName(final String argument) {
...
}
I fail to grasp why final is needed here. Is it only because of the field immutabilty? What big picture am I missing in this case?
I am getting the above error and am not sure which direction to proceed. In the class, the only way we have discussed getting user input is by System.in.read. I have searched and apparently found better methods for getting user input, but wanted to stick with what has been presented thus far.
Assignment Directions:
1. Create a new class named “valuemethod”
2. Create a new method named “Main”
3. In Main Write the code that will call the method EnterPay and YearlySal
4. Create a new method named “EnterPay”
5. In the EnterPay method Write the code that asks the user to input their hourly wage. Use the formula to calculate their yearly salary: wage * 2040. Return the yearly salary to the main method
6. In the main method write the code that will display this: “Your yearly salary is:
Java Code:
package valuemethod;
public class Valuemethod
{
public static void main(String[] args)
//throws java.io.IOException -- moved to EnterPay
[Code] .....
The 2 minute drill from page 69 SCJP kathy and bert book, says regarding Interfaces, that - "A legal nonabstract implementing class must not declare any new checked exceptions for an implementation method."
When I try the below given code in eclipse , it does not throw any errors . (Here I have tried to throw NullPointerException from testFunc whereas the interface function throws IllegalStateExc)
package abstracttesting;
public class StaticCheck implements check{
public void testFunc() throws NullPointerException{
// TODO Auto-generated method stub
} public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
interface check{
void testFunc() throws IllegalStateException;
}
While reading the design patter book, i got one doubt ,There is a List an interface having sub classes ArrayList, LinkedList etc.,
Q1) My question is Why they declared the List as interface rather than Abstract class?
Q2) i read some site -
List l = new ArrayList(); Why it is GOOD line?
ArrayList l = new ArrayList() ; Why it is BAD line?
Answer required with detailed information for Q1 and Q2.
I have the following double linked list and I'm supposed to order it descending (reverse) using the printInReverse() method; since the list orders itself ascending when the numbers are added, how could I order it descending in this method? Here's the code without implementing descending/reversing methods:
package test;
import java.util.Scanner;
public class MyList {
private Scanner userInput;
private Integer selectedOption;
private MyListElement firstElement = null;
private boolean exitRequested = false;
[Code] ....
I tried to declare a previousElement variable but I didn't figure out how I'd do that.
you can also refer this link Local variables in java?Local variables in java?To meet temporary requirements of the programmers some times..we have to create variables inside method or bock or constructor such type of variables are called as Local Variables.
----> Local variables also known as stack variables or automatic variables or temporary variables
----> Local variables will be stored inside Stack.
-----> The local variables will be created while executing the block
in which we declared it and destroyed once the block completed. Hence the scope of local variables is exactly same as the block in which we declared it.
package com.javatask.in;
class A{
public static void main(String args[]){
int i=0; // Local variable
[code]....
I write the following statement:
int num1 = (int)( 1000 * ( generator.nextFloat() ) );
System.out.printf("%d", num1);
and I get an error!
The weirdest thing is that 'num1' does NOT show in variables window. How can it be?
So like, in lua programming language you can do things like,
Array = {1, 2, 3, abc = 5, efg = {123, 456, 789, hij = {"tests","works!"}}, hij = true}
Array[1] = 5
Array[3] = true
Can you do atleast something like this in java or?
I would like to do this because if let's say I was making a game, I could define what tiles are passable and which are not and then their location or something, so like this:
//p (passable) stands for if possible to walk on
//c stands for tile image
t = ["grass.png","water.png","chest.png"]
Tiles = [
[p = false, c = t[1], x = 3, y = -2 ],
[p = true, c = t[0], x = 4, y = 3 ],
[Code] ....
Or something...
I am unable to understand the meaning of this sentence "final reference variables must be initialized before the constructor completes.",What is trying to imply?
View Replies View RelatedABC is a company that designs and prints personal business cards. The company has asked you to write a Java application to display the layout of the information in a typical business card order. Data items in a typical business card include the customer's name, address, city, state, postcode, home phone number, and work phone number.
Write, compile, and test a Java class that displays these data items in a command window. Alternatively, you could also create it using a dialog box. Please include appropriate comments in your class.
Please named your class BusinessCard(LIM).java. (eq. BusinessCardLIM.java)
I have An Issue With My Java Applet. Im Trying To Share My Variables With Another Class, But Its Not Working.
Class 1
package com.Tobysmith10.game.main;
import java.applet.Applet;
import java.awt.Graphics;
public class Game extends Applet{
public void init(){
setSize(850,480);
public void paint(Graphics g){
g.fillOval(x,y,20,20);
}
}
Class 2
package com.Tobysmith10.game.main;
import java.applet.Applet;
public class gameLoop extends Applet implements Runnable{
public int x, y;
public void run(){
while(true){
x = 100;
y = 100;
}
}
}
So im sharing the x and y variables with the Class 1 , but I get yellow lines under it and when i run the program, it crashes, how do I get class 1 to recognize the variables from class 2 ?
okay so it says that java int short and byte variables are the same thing. They take whole numbers. But what is the point of byte and short to even exist if int covers it all? Is the short and byte just for fun?
View Replies View RelatedA method is declared to take three arguments. A program calls this method and passes only two arguments.Will it take the third argument as
1 null
2 void
3 zero
4 Compilation error
Does child class gets a copy of the methods and variables of parent class?
public class test1 {
public static void main(String a[]) {
Child c = new Child();
c.print();
[Code] ....
why is the output 1?
How do you declare methods for a class within the class whilst objects of the class are declared else where?
Say for instance, I have a main class Wall, and another class called Clock, and because they are both GUI based, I want to put a Clock on the Wall, so I have declared an instance object of Clock in the Wall class (Wall extends JFrame, and Clock extends JPanel).
I now want to have methods such as setClock, resetClock in the Clock class, but im having trouble in being able to refer to the Clock object thats been declared in the Wall class.
Is this possible? Or am I trying to do something thats not possible? Or maybe I've missed something really obvious?
Take this:
class test
{
static int i=j;
static int j=10;
.....
this will give illegal forward reference ....
but this will compile successfully ..
class test
{
static int i=test1();
static test1()
{
return 20;
}
}
.....
plz assume we have main method in both cases ..
java would be loading all static members first and would be assigning default values .. and then will be running all the initializers from to bottom ..Why second case is a compile success and not first .. as in second also test1 method is declared after its usage ..
I have an ArrayList of employee and ArrayLsit of bosses, and I want to keep those people in a temporary ArrayList , then ordain alphabetically by name, to sort I use the interface comparator.
The problem comes when I will order 2 ArrayList(workers and bosses), because every time I call I use these functions or not is ordered (sortByNameAlphabetical())
public class Employee {
private String name;
public String getName() {
return name;
}
@Override
public String toString() {
return name ;
[Code]...