How Many Ways To Create Object In Java
Mar 21, 2014How many ways to create an object in java ?
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Servlets :: Create Corresponding Java Object?
Sep 18, 2014I get an json from http request. I want to create a corresponding Java object.
is there any automated mapping? Something called pojo or something else?
Create A Balloon Object In Java
Sep 19, 2014Programming Assignment #2
(Using an Existing Class: Creating Objects and Calling Accessor and Mutator Methods)
I. The Assignment
This assignment is to write a "test" class (aka: a "driver" class or "client code") that uses the class Balloon.java, available on the class web page.
To use the Balloon class, download it and store it in the src folder of your NetBeans project. Make sure you save it as Balloon.java.
The best way to learn how to use the Balloon class or any other Java class, for that matter - is to consult the documentation, Balloon.html (online). You can also read the javadoc comments that appear just above the class declaration and above each method declaration, which explain what each method does, what the method's parameters are, and what value if any - is returned by the method. The html support pages are generated from these comments.
-Review declaring variables, creating objects, calling methods that return a value vs. void methods, and accessor and mutator methods before beginning. To receive credit for this assignment, you must not modify the Balloon class in any way!
II. Your BalloonTester Class
Your BalloonTester class will have only a single method "main" and will perform each of the following operations, in the exact order listed below. Each operation may be done in one or two statements. Make sure you follow directions faithfully, and note that once you have done step 3, you can copy and paste it to do steps 6, 9, and 12.
1.Create a Balloon object with a name of your own choosing and an altitude of 100 meters.
2.Create a second Balloon object with a name of your own choosing, and specify an initial altitude of -100 meters.
3.Call the accessor methods of the Balloon class to get the name and altitude of each Balloon object. Print the data, one object per line.
4.Make the object you created in step 1 ascend to an altitude of 250 meters.
5.Call the adjustAltitude method to increase the altitude of the object you created in step 2 by 150 meters.
6.Call the accessor methods of the Balloon class to get the name and altitude of each object. Print the data, one object per line.
7.Call the adjustAltitude method to decrease the altitude of the object you created in step 1 by 150 meters.
8.Make the object you created in step 2 descend to the same altitude as the other object. You may assume that the other object is at a lower altitude.
To get credit for step 8., the statement(s) you write must always work, regardless of the actual altitude of the second object. It cannot depend on you knowing the altitude of the second object, but must utilize the fact that the object knows its own altitude. In other words, if you use a literal in any way to set the altitude, it is not correct.
9.Call the accessor methods to get the name and altitude of each object. Print the data, one object per line.
10.Move the object you created in step 1 to an altitude that is four times its current altitude. As in step 8, the statement(s) you write must work for any altitude and may not depend on you figuring out the new altitude beforehand.
11.Attempt to move the object you created in step 2 to an altitude that is 150 meters below its current altitude.
12.Call the accessor methods to get the name and altitude of each object. Print the data, one object per line.
and this is the Balloon.java given:
// File: Balloon2.java
// Modified Balloon class has overloaded constructors
/**
* A class to represent a hot-air balloon. Balloon objects have a name and an altitude.
*/
public class Balloon2
{
// instance variables
private String name ; // name of the balloon
private int altitude; // altitude (height) of balloon in meters
[Code] ....
Create Object Deriving From PrintingClass And Use That Object To Print Text
Apr 9, 2014Task:The main method of the class Things below creates an object called printer deriving from the class PrintingClass and uses that object to print text. Your task is to write the PrintingClass class.
Program to complete:
import java.util.Scanner;
public class Things {
public static void main(String args[]) {
String characterString;
Scanner reader = new Scanner(System.in);
PrintingClass printer = new PrintingClass();
System.out.print("Type in the character string for printing: ");
characterString = reader.nextLine();
printer.Print(characterString);
}
}
// Write the missing class here
Note: In this exercise the solution is part of a conversion unit where many classes have been declared. Because of this the classes are not declared as public using the public attribute.
Example output
Type in the character string for printing: John Doe
John Doe
My Class:
class PrintingClass {
public void print(){
System.out.println(characterString);
}
}
Three Ways To Print Dash Character
Feb 14, 2014Find three ways to make the program below print 20 copies of the dash character '-' by changing /adding just one character.
int i,n=20;
for(i=0;i<n;i--){
System.out.println("-");
}
I found two solutions but till now not able to find the third one. The two solutions are
int i,n=20;
for(i=0;i<n;n--){
System.out.println("-");
}
and,
int i,n=20;
for(i=0;-i<n;i--){
System.out.println("-");
}
Two Ways To Pass Arguments To Methods
Nov 14, 2014I have a test that covers Objects & Classes, Importing Classes and Polymorphism. One of the essay questions will be: Explain two ways to pass arguments to methods and give examples. I was reading the book and found Pass by Value and Pass by Reference. Is this the two ways to pass arguments?
View Replies View RelatedServlets :: Better Ways Of Securing Webpages Access
Jul 10, 2014I wish you could share some methods for securing access to webpages of websites you had had a hand on? I know of:
- asking for user credentials from an entry page and processing them inside a javabean to confirm they are equal to those kept in the system before granting further access.
- masking servlets paths in web.xml
- hiding client scripts in libraries that are kept on server
Do you know of other methods?
User Input Random Numbers Then Program Sort Them In Different Ways - Missing Return Statement
Apr 7, 2014I have been assigned to write a program that has a user input random numbers then the program is to sort them in different ways. I have the coding for the different sorts but, I have an error saying that I am missing a return statement in the "Bubble" method. I am trying to return "arr[i]" in the "for loop" which gives me this error, and when I try to take the "return arr[i]" outside of the "for()" loop the error reads the it cannot locate variable "i".
import java.awt.* ;
import java.awt.event.*;
import javax.swing.*;
public class SwingSorts extends JFrame implements ActionListener
{
JRadioButton bubble;
JRadioButton selection;
[Code] .....
How To Create And Re-use Object Types
Mar 17, 2014 how objects relate to classes and how you can create and re-use object types.on that point, but this has me baffled. I most certainly do not have a firm grasp yet on passing things to and from methods that just makes my head hurt. SO anyway I tried out one of the code examples:
/* ElectricGuitar.java */
class ElectricGuitar {
String brand;
int numOfPickups;
boolean rockStarUsesIt;
[code]...
But I just realized this thing has no main method and only one class defined.....so I guess I just tried to compile.
Why Can't Create Object Of Abstract Class
Jul 18, 2014Why we can't create object of abstract class ,when we can create its constructor?
View Replies View RelatedCreate New Scanner With The Specified String Object
Jul 4, 2014//Scanner Test
String stream2 = "ab34ef
56";
// create a new scanner with the specified String Object
Scanner scanner = new Scanner(stream1);
// find a string "World"
[Code] ....
Matched expression found by findInLine: 34
ef56
is new line? right?
The java.util.Scanner.nextLine() method advances this scanner past the current line and returns the input that was skipped. This method returns the rest of the current line, excluding any line separator at the end.
then 56 is in new line and it must return ef.What is the problem?
Can't Create Object Of PrintStream Class
Dec 11, 2012I know that System is a final class and it cannot be instantiated, out is a static final variable of type PrintStream in System class and println is a method in PrintStream class.Still I don't understand why we use System.out to call println() method.To my knowledge a method can be called using an object reference, in case of static behaviors we use classname. Then why here we are using System.out.println? Can't we just create an object of PrintStream class and call the println() method as PrintStream class can be instantiated.Are there any ways of calling a method apart from those I know(I have mentioned above what I know)?
View Replies View RelatedCan Create Object For Abstract Class
Oct 5, 2014Animal ob1=new Lion();
Here we create ob1 for Animal class or Lion class.
public abstract class Animal {
public abstract void eat();
public void breathe(){
[Code] ....
Why ACM Isn't Letting To Create Object From Different Class
Apr 16, 2014I'm curious why ACM isn't letting me create an object from a different class, maybe I am missing something?
my main class:
import java.awt.Color;
import acm.program.*;
import acm.graphics.*;
public class MyClass extends GraphicsProgram {
private static final int WINDOW_W = 500;
private static final int WINDOW_H = 500;
[code]....
I have also noticed when trying to extend 'ConsoleProgram' it does the same thing with line printing (except when using system.out).
StringHandler - Create Instance Of Object In A Loop
Oct 26, 2014I can't figure out where to create the StringHandler object. My code should take a string as input, then create StringHandler object ord with the string input. This should repeat until cancel is pressed, then ord should be sent to the Utskrift-method (a print method).
If I do like this, null is also sent to Utskrift. I dont want that to happen.
If I put StringHandler last in the loop ord can not be resolved.
String text = "";
while (text != null){
text = showInputDialog(null, "Enter text:");
StringHandler ord = new StringHandler(text);
if (text == null){
[Utskrift(ord.getNumber(), ord.getString(), ord.getWords());
break;
}
}
Create Method In Main Class And Use It On Object
Feb 26, 2015I've been writing classes over and over for school. So I create a class outside of my main class. I create a new constructor and then create objects from my main class. I hope that makes sense. So i use methods in that class to work with the object. So I have an object name I've created <dot> method name. So I can create objects and then use methods from the class, but I'm wondering can I create a method in my main class and use it on that object? I don't understand how to do that.
View Replies View RelatedCreate Country Object And Store In Array
Oct 12, 2014Write a program that prompts the user for information about some countries, creates an object for each country, and then stores the objects in an array. After the user has entered information about all the countries, your program should print out which countries in the list have the smallest and largest area and population density. Assume the user will enter information about at least one country but that the program will not have to store more than ten countries in the array. The user will indicate that they are done entering countries by typing "DONE" for a country name. Here is an example of what your program must look like when it is executed (user input is shown bold)
Please enter the name of a country: United States
Enter the area in square km and population of United States: 9827000 310000000
Please enter the name of a country: Mexico
Enter the area in square km and population of Mexico: 1973000 122300000
Please enter the name of a country: Canada
Enter the area in square km and population of Canada: 9985000 35160000
Please enter the name of a country: Liberia
Enter the area in square km and population of Liberia: 111370 4294000
Please enter the name of a country: DONE
Liberia has the smallest area at 111370 square km.
Canada has the largest area at 9985000 square km.
Canada has the smallest population density at 3.521282 people per square km.
Mexico has the largest population density at 61.986822 people per square km.
I don't know, I'm really confused with this Java program. I don't know how to do the main part of the program where the user inputs, array, and the output.
// Access the Scanner and ArrayList class by importing the java.util package.
import java.util.Scanner;
/** Project - A Country Object
* The purpose of this program is for the user to enter some information at most 10 countries. After the user has entered information about all the countries, the program should print out which countries in the list have the smallest and largest area and population density.
*/
public class Country
{
private String countryName;
private int theArea;
private int thePopulation;
public Country(String countryName, int thePopulation, int theArea)
[Code] ....
Pixel Manipulation - Create Art Object Using JPG Or BMP At Indicated Location
Nov 20, 2014I am working on a project using pictures and am having some trouble. My assignment is to take a jpeg, and reflect it(over an imaginary x-axis so to speak). As this is my first time working with images, I am very lost. My approach was to take "pixel 0" and have it swap places with "pixel max". Theoretically, I believe I would only need to do this for the first 50% of the pixels, as each flip works on 2 opposite pixels. With my code thus far (the reflect() method), I print the left half of the image. Note: I must use pixel manipulation. I cannot use graphics.
public class MyArt
{
private Picture image;
/**
* Create an Art object using the jpg or bmp at the indicated location
*/
public MyArt(String filename)
{
image = new Picture(filename);
[Code] .....
RMI :: Find / Create A Registry And Binding Object
Jul 30, 2013My program TestBind0 (code below) tries to find/create a registry and bind an object.
Find/create: it first tests if there is already a registry on that port; if not, then it tries to create one.
The program tries to find/create the registry on ports 40654, 50876, 30321, 33445, 1099, in this order, until it succeeds in both creating the registry and binding the object. Why does TestBind0 throw for each attempt
java.rmi.ConnectException: Connection refused to host: 192.168.1.64; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:601)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:198)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:184)
at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:322)
[Code] ...
In reg.rebind("TestBind0", obj);even when I have specified -Djava.security.policy==all.policy, with file all.policy in the current dir, containing
grant {
permission java.security.AllPermission;
};
The program is run using command
java -cp bin -Djava.security.policy==all.policy TestBind0
The code:
import java.rmi.*;
import java.rmi.registry.*;
import java.rmi.server.*;
import java.util.*;
public class TestBind0 extends UnicastRemoteObject implements Counter {
private static final long serialVersionUID = 1L;
protected int count;
[Code] ....
Create Object Of List Type Such As Text File?
Dec 27, 2014I want to create a program where I need to create an object of list type such as text file will contain nos like 1,2,3,4,5 and write into text file and delete the in FIFO order i.e 1,2,3,4,5...how i can achieve to write a program? I tried bt everytime got concurrent modification exception or Array out of bound exception.
View Replies View RelatedHow To Create Object To Be Null If Class Constructor Parameter Is Int
Mar 8, 2015I have a class of Date with a constructor with 3 parameters in it. Those 3 parameters are int data type just to enter month, year, day.
I have another class called Author which has a constructor of Date diedDate; as a parameter passing to the Author constructor.
I was asked to call the Date parameter is null, call the default constructor but I thought for the Date parameter I could only enter something like 0,0,0 instead of typing in null, null, null because null is for String data type isn't it?
How To Pass Object Type To A Method / Then Create Instance
Aug 9, 2014Essentially, the code I want is:
public void randomCreate(ParentObject obj){
int x = random(0-4); //pseudo
int y = random(0-4); //pseudo
create new ParentObj(x,y);
}
ParentObject is actually abstract, so you would only ever pass one of its children objects to it, and a child object of that type would be created. It seems like there should be a way to pass a type, rather than an object, and then create an instance later down, but I don't know if that is actually possible, or if it is poor programming style.
Swing/AWT/SWT :: How To Create A Table Where The Header Is A Custom Object
May 14, 2014I'm trying to create a table where the Header is a custom object.
The custom object would be something along the lines of
public MyColumnObject
{
String myLabel;
ArrayList dataForDropdowns;
int defaultColumnIndex;
int modifiedColumnIndex;
String tooltip;
}
This is simpler then what I want to do, but it's the basic concept. I want the column header to render the myLabel for the visual (at least at first). I want this render to be applied to however many columns I have, which will differ from table to table, but I always want the column header of each column to be of type myColumnObject.
I thought somethinglike this would work, but I'm getting java.lang.ClassCastException: java.lang.String cannot be cast to myColumnObject which makes sense, but I thought that I would be getting back my object.
p.s. I re-labeled all my code from my actual project, so if something looks off, it was probably just the re labeling.
public NewTestTable(MyColumnObjects[] fields)
{
setModel(new TestObjectTableModel(
new Object [][] {
},
fields
) {
private static final long serialVersionUID = 1L;
public boolean isCellEditable(int rowIndex, int columnIndex) {
[Code]...
Create A New Instance Carte Of Object Carti Using Constructor
Mar 30, 2014what have I done wrong n the following code? I'm trying to create a new instance carte of object Carti using the constructor and then to insert a row into a table created with SQL.The error I'm getting is:
Exception in thread "main" java.lang.NullPointerException
at Carti.Carti.InsertCarti(Carti.java:103)
at Main.main(Main.java:37)
Java Result: 1
BUILD SUCCESSFUL (total time: 28 seconds)
The line Main.main(Main.java:37) is when I try to insert the row.
The line Carti.Carti.InsertCarti(Carti.java:103) is when I do the
PreparedStatement st = conn.prepareStatement("insert into Carti (Id,titlu"
+ ", descriere, autor, editie, anPublicare) values (?,?,?,?,?,?)");
Here is the code (Main and Carti Classes)
import Carti.Carti;
import Imprumut_Carti.Imprumut_Carti;
import Membrii.Membrii;
import static com.sun.org.apache.xalan.internal.lib.ExsltDatetime.date;
import static com.sun.org.apache.xalan.internal.lib.ExsltDatetime.date;
import java.sql.SQLException;
import java.text.DateFormat;
[code]....
How To Create New Customer Object Each Time User Chooses 1 As Option
Feb 17, 2015import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
public class App {
public static void main(String[] args) throws IOException {
Scanner keyboard = new Scanner(System.in);
System.out.println("Please Select an option > ");
[Code] .....
EJB / EE :: Create Stateless Bean That Instead Of Returning A String Returns Object
Jul 31, 2014I'm training myself with the EJB 3 technology. I would like to create a stateless bean that instead of returning a String, it returns an object. I tried in the same way I did with the first exercise, but I'm getting several errors.
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