Assuming that we have two classes B and C which inherit from class A. What is the best way to pass a parameter from an object of class B to an object of class C by the use of class A without using static variable and without defining a get function in B?
View RepliesI 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?
I want to know is there any way we can call parent class method using child class object without using super keyword in class B in the following program like we can do in c++ by using scoop resolution operator
class A{
public void hello(){
System.out.println("hello");
}
}
class B extends A{
public void hello(){
//super.hello();
System.out.println("hello1");
[code]....
can we pass private final class object to another class constructor?
View Replies View RelatedHow to create object for "class B" and call the "function_B" from other different class D where class D has no connection with class A? Here is my program.
public class A(){
void print(){}
}
class B{
void function_B(){}
}
class C{
void function_C(){}
}
Here, A, B, C are in the same package. But class D is in different package.
I am a beginner here at JAVA and I am trying to program a Gratuity Calculator using both interface class and object class but it keeps on compiling with errors saying "cannot find symbol".I tried everything to fix it but it just keeps on stating symbol.
[CODE]
public class GratuityCalculator extends JFrame
{
/* declarations */
// color objects
Color black = new Color(0, 0, 0);
Color white = new Color(255, 255, 255);
Color light_gray = new Color(192, 192, 192);
[code]....
Design a class named Person and its two subclasses named Student and Employee. Make Faculty and Staff subclasses of Employee. There is also a MyDate class as explained below. A person has a name, address, phone number, and email address. A student has a status (freshman, sophomore, junior, or senior). Define the status as an integer which can have the value 0 (for "Freshman"),
1 (for "Sophomore"),
2 (for "Junior"), and
3 (for "Senior"),
but don't allow the status to be set to any other values. An employee has an office, salary, and dateHired. The dateHired is a MyDate field, which contains the fields: year, month, and day. The MyDate class does not explicitly inherit from any class, and it should have a no-arg constructor that sets the year, month, and day to the current year, month, and day. The MyDate class should also have a three-argument constructor that gets three int arguments for the year, month and day to set the year, month and day.
A faculty member has office hours and a rank. Define the rank as a String (for values like "Professor" or "Instructor"). A staff member has a title, which is also a String. Use data types for the fields as specified, or where one is not specified, use a data type that is appropriate for the particular field. Write a test program called TestEveryone.java that creates a Person, Student, Employee, Faculty, and Staff object, and invoke their toString() method (you don't need to call the objects' toString() method explicitly).
Note: Your MyDate.java class is the object class that your dateHired field is created from in the Employee.java class.
Do not use the Person, Employee or Faculty classes defined on pages 383 and 384 of the book. Create new ones.Here is the code I have so far concerning the employee and MyDate.
public class Employee extends Person {
private String office;
private double salary;
//private MyDate dateHired;
//7 argument constructor for employee
public Employee(String name, String phoneNumber, String email, String address, String office, double salary /*MyDate dateHired*/) {
super(name, phoneNumber, email, address);
[code]....
In the process of creating a new class, I need to move my main method from the class SaveDate to the class DynamicTest. Below I have listed the code of both classes.The objective is to be able to run my program from the DynamicTest Class. I need understanding the process of moving my main method to a different class and creating an Object of a class and calling its method.
public class SaveData {
private static final Map<String, Object> myCachedTreeMap = new TreeMap<String, Object>();
public static final List<String> getLines(final String resourceParam, final Charset charset) throws IOException{
System.out.println("Please get: "+resourceParam);
if (myCachedTreeMap.containsKey(resourceParam) ) {
// Use the cached file, to prevent an additional read.
[Code] ......
Suppose you have a generic Dog class of the pet type that implements a DogInterface of the pet type. What is the difference between;
DogInterface<pet> Rex = new Dog<pet>();
and
Dog<pet> Tye = new Dog<pet>();
In what situations might you want to use Rex instead of Tye?
"You might wonder what happens when a static synchronized method is invoked, since a static method is associated with a class, not an object. In this case, the thread acquires the intrinsic lock for the Class object associated with the class. "What is a Class object associated with a class. Google search rather finds material about the Object class.
View Replies View Relatedi want to pass an object of type Software to assign it to a computer from Computer class...
i should note that computer and software are arrays of objects thats the variable and method to set software in Computer class
private Software[] software;
public void setSoftware(Software software,int index){
this.software[index]=software;}
note: the user choses the a computer from a list and a software as will
for example the program will show the user 2 computers
0 for computer: apple, Model: mac mini, Speed: 2.8
1 for computer: sony, Model: vaio, Speed: 2.2
the user enters the index he wants then the program will show a list of software to add to the computer selected
the error I'm having is run time error Exception in thread "main" java.lang.NullPointerException and it points to these 2 lines
1.comp[Cch].setSoftware(software,Sch);
2. the method setSoftware
every thing is running correctly but this step above
Cch= the chosen computer index
Sch= the chosen Software index
why am i getting an error and how to fix it?
I've 3 classes.
1. Circle
2. GetInputFromUser
3. testCircle
package ABC;
public class Circle {
private double radius;
public double getRadius() {
return radius;
[Code] .....
In the testCircle class, in the line: getRadius = ui1.GetInput();
It's showing the error: The method GetInput(float) in the type GetInputFromUser is not applicable for the arguments ()
And when I do: getRadius = ui1.GetInput(rad);
It's showing the error: rad cannot be resolved
I have an object that has an instance of another object class as its parameter :
CombinationLock oneHundred = new CombinationLock(28,17,39);
Locker Mickey = new Locker(100, "Mickey", 3, oneHundred);
This is for a locker, which has a combination assigned to the student. Within the locker class I have the following constructor:
public Locker(int locker, String student, int numberOfBooks, CombinationLock combo) {
this.locker = locker;
this.combo = combo;
this.student = student;
this.numberOfBooks = numberOfBooks;
}
combo is the private CombinationLocker object I created within the Locker class. Do I need to pass the combo object on to the CombinationLock class? For reason, I do not comprehend, the combination password from the main class is not passing through to the CombinationLock class, and the combination values are all zero.
I have a value object class and it has the below member
XMLDocument request = null;
Should I instantiate it in the VO class as
XMLDocument request = new XMLDocument();
or leave it null and let the calling program instantiate it?
What's the proper way to do it for Value Object classes in java ?
So the first thing we did was make a program called memory calculator. now we are supposed to make a sub class that modifies the program to also do exponents and natural logs. Then to make a new class that acts as the driver for what is now called the scientific memory calculator which includes the exponent and log. I have watched this through debug and im a little confused. first off it creates a variable for currentValue in current and in sci which are my instances, which i dont think is what i really want to do, I am unsure how to get the things in the Scientificmemcalc to do stuff without calling them directly. so when i try to do the power feature it does everything correct but it sets the sci current value to the correct answer, and now i cant figure out how to pass it on to the current current value.
This is the memory calculator :
public class MemoryCalculator {
public static void main(String[] args) {
MemoryCalculator current = new MemoryCalculator();//creates an instance
int choice = 0;
do{//main loop
System.out.println("Current value: " + current.getCurrentValue() + "
[Code] .....
I'm preparing for an exam in a course focusing on algorithms, code:
Java Code:
protected static class Node<E> {
public E data;
public Node<E> left;
public Node<E> right;
[code]...
Are they objects of their own class?
We know that all classes in Java extend the Object class. But methods in Object class are declared as public.I think if they were declared as protected, then also there wont have been any issue. So, what is the reason behind making them as public?
View Replies View RelatedI've been referencing my text and a few other sites to assist in building this class...and I'm still uncertain of the purpose of a few of the methds: next(), hasNext().
Also, I have not found a clear explanation of the following code example: tail.next = tail; There are several instances of this in the code below....I'm just not sure exactly how this assigns the value to the next object in the other class..?? ??
public class MySinglyLinkedList<T> implements SinglyLinkedList<T>{
protected NodeList<T> head, tail, current, newNode;
String name;
int size = 0;
public MySinglyLinkedList(){
head = null;
tail = null;
[Code]...
I have finished a Java 101 class but the most we did was create a gui for a timer program. I figure I need more training and every book I pick up wants to teach me hello world and the difference between a class and object again.
View Replies View RelatedI am trying to get an object to display twice from a class in an applet.
Java Code:
if (label == 4) {
game.stop();
timer.start();
result.setText(" You Have Destroyed the World");
marFoundDisplay.setText("Martian: " + String.valueOf(mCount));
jupFoundDisplay.setText("Jupiterian: " + String.valueOf(jCount));
highScoreDisplay.setText("HighScore : " + String.valueOf(HighScore));
j.draw(g, 350, 150);
j.draw(g, 350, 150); mh_sh_highlight_all('java');
Obviously calling it twice doesn't get the desired effect, I'm ultimately trying to get them to be side by side in the middle of the applet, but clearly what I've done won't achieve that.Can you provide me an example that would allow me to display the code below to have the item be displayed twice side by side?
Java Code:
j.draw(g, 350, 150); mh_sh_highlight_all('java');
I don't know why class Object have two PROTECTED method -- clone() and finalize(). And in JUnit's source code, I notice that kent write :public class AClass extends Object {}I really don't understand what diffrient frompublic class AClass {}
View Replies View RelatedI have a class for employees. This class has basic information for the employee but no real pay information. And 2 subclasses, one for employee's paid for hourly rates and one for those paid a yearly salary. Each subclass has their own pay() method, that calculates and returns their pay and extra fields relative to calculate that.
I'm just curious, if I do this and create an object for an hourly paid employee like so:
Object hourly1 = new HourlyEmployeeWilson("John Doe", "123 Tech Street",361961,"Human Resources", 0,12.50,50);
How can I utilize that classes public method of pay() to gather this instance (or hourly paid employee)'s pay? I've tried doing so via:
System.out.println(hourly1.pay());
But I get
DriverPayWilson.java:9: error: cannot find symbol
System.out.println(hourly1.pay());
^
symbol: method pay()
location: variable hourly1 of type Object
1 error
I have a servlet that generate a list of objects named "Alerte". I display this list in my jsp and I want the user to be able to delete one of them by clicking on it. Data are stored on Google Datastore. My problem is that I don't know how to pass the current object from the loop of my JSP page to my java class.
<%
List<Alerte> alertes = (List<Alerte>) request.getAttribute("alertes");
%>
<c:forEach var="alerte" items="${alertes}" >
<table>
<tr>
<td>Name:</td>
<td>${alerte.name}</td>
[Code] .....
I have started working on a little project in my free time. It is just a simple text rpg that runs in a counsel window. I have 5 files each file contains 1 class.
public class SomnusCharacter {
private String gender = "";
private int age = 0;
private String race = "";
private int level = 0;
private int xp = 0;
[Code] ....
The chain of events right now is:
1. MainMenu is run
2. If user inputs n CreateCharactor is run
3. User inputs name, age, ect in SomnusCharacter object made in CreateCharacter
4. Intro (just rough demo for testing purposes) is run
5. If user inputs m Menu is run
6. Menu calls and prints out all the information from the object made in CreateCharacter
Step 6 is where I am having my problems. How can I reference (lets say the SomnusCharacter object made is called player) player from my Menu class? I know that if I made a new character that it would just create another SomunsCharacter object with the default values again.
Why we can't create object of abstract class ,when we can create its constructor?
View Replies View RelatedI have make the immutable class as below, Now my question is how I can test if my this class/object is immutable
package com.learning;
import java.util.*;
import java.util.Map.Entry;
public final class ImmutableTest {
private final int id;
private final String name;
private final HashMap<String, String> hm ;
[Code]...
How I can Test If it is immutable class without looking ?