Java Does Not Support Multiple Inheritance Using Classes
Aug 16, 2014
I studied that java does not support multiple inheritance using classes. It is fine practically, but I have still a question in mind:Lets see the below code.
class Test{
------
------
}
class MyTest extends Test{
---------
---------
}
Here, as we know that that Object is Super class for every class in java. and I have already extends a Test class in MyTest.My question is: How is it possible to extend features of two class at the same time?
Theoretically,
MyTest extends Object &
MyTest extends Test.
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Apr 11, 2014
This is my assignment.
Identify how multiple inheritance is possible in Java with interfaces.
Write a java programme with appropriate classes to demonstrate the above.
Hint: both inheritance and interface concepts are necessary.
For the project name in netbeans, use your id and the name "assignment" separated by underscore,
E.g. 9876543_assignment
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Jan 12, 2014
how can i implement multiple inheritance in java using interfaces. if interfaces have some methods having same name then how to distinguish that ?
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Apr 3, 2014
how to do multiple inheritance without sing interface in java?
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Nov 19, 2014
I am writing small pieces of code to make sure I understand Java basics and I have the following.
package teams1;
public abstract class Team1{
private String sport = new String();
public abstract String getSport();
public abstract void setSport();
}
import teams1.*;
[Code] .....
It doesn't compile because sport is private in the super class, but I thought FootballTeam1 would inherit it's own copy of sport because it is extending Team1.
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Jan 4, 2015
I have a working program, except that it does not calculate the credit hours and the financial aid. When I enter an input, it works, until it should show the student name, credit hours and financial aid. the error i get from the command is "Hours invalid for false student". Here is the program i think i might have the problem.
import java.text.DecimalFormat;
public abstract class Student
{
//initialise variables
String name;
int creditHrs;
[Code] .....
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Apr 6, 2014
I am trying to figure out how I can most easily make it easier to make new types of units in my game. I have buildings and ships, and would like to know how I could make it easy to add new units. I have been recently told about interfaces, and have worked with inheritance a little bit.
What I would like to able to do is have it so that all of the variables and methods common to all ships could be stored in a superclass or interface, and same with the buildings. I would also like to be able to assign behaviours to the buildings and ships, maybe as interfaces, which could contain all of the methods and variables required for the functions of that ship or building.
For example, creating a new type of building that can shoot, build ships, and can regenerate nearby ships. So it would possible inherit all of the variables and methods common to all buildings, such as health, image, x, y, getX(), getY() etc. But it would then also gain the variables and methods essential for its functionality, such as shootRange, shoot(), regenRate, etc.
How could this best be achieved?
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May 5, 2015
I'm very new to Java, and I am creating a program that takes multiple user input to create one face. I have a class for the eyes, nose, lips, and headshape. For some reason, my program is not drawing the graphics. ***for question purposes, I have only included my head shape class and my test class****
my "test" class:
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class FaceTest
{
public static void main(String[] args)
{
String head = JOptionPane.showInputDialog("Would you like a circle, square, rectangle shaped head?: ");
[Code] ....
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Feb 8, 2014
As what i understand, Generalization is also know as Inheritance and Aggregation. They may or may not co-exist in order for a class to work. The subclass and the super class
And on the other hand, multiple inheritance is not allowed in Java, how these two differs.
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Feb 7, 2015
why Java does not support return type in method overloading. I coded following and it compiles and runs without any errors.
class Ideone
{
public static void main (String[] args) {
sum(3,5);
[code]....
If Java did not support overloading based on return type, this program should not work, right?
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Oct 25, 2014
I have to make a retail item class that has description, price and quantity. I then have to make a CashRegister class that calculates subtotal, tax, total and displays it (toString). I also have to make a driver class to call the methods from main. I have no clue what I am doing and what I have done does not work. I am trying to make it sort of like a cart, in the CashRegister it should ask the user to enter the description, quantity purchased and the price. Then it would send that to the arraylist of retailitem. I am having trouble using those items in my other methods and then do not know how to call those in the driver class.. So here are my classes:
public class RetailItem {
private String description;
private int quantity;
private double price;
public RetailItem(){
description = "";
quantity = 0;
[Code] ....
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Apr 25, 2014
I was trying to play around a little bit after learning creating multiple classes and stuff.However,i encountered a strange problem with reading a value from the user and then storing it in a variable.The usual way i do it is
Scanner variableName=new Scanner(System.in);
System.out.println(variableName.nextLine());
But when i trying to print the contents of the variable "variableName" the compiler throws a lot of errors .I am attaching how i have tried that out in my code
import java.util.Scanner;
class laptop{
private String modelNumber;
private boolean hasFan;
private float ramSpeed;
protected int numCores;
//private String input;
[code]....
Without the setInfo() in the laptop class the program functions as desired but i intend to ask the user if he wants to modify something and then reflect the same.
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Mar 1, 2015
I have recently start learning about objects and classes in java. I understand that in order to use multiple classes in one file you need one class to be public and the rest are private. But after that I don't understand how to invoke the private class in the public class. I thought if I tried programming on my own I can have a better understanding of it, but had no success.
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Jan 31, 2015
I'm having problems with this I've code like:
Java Code:
Public Class{
Objects
Constructor(){}
ActionListener Method(){}
Main Function()}
[Code]....
but I cannot declare variables in this method, how can I do this what can be the simplest method?
In addition: I've a marksheet class, a calculator class, & in main class I've 2 buttons one for marksheet & one for calculator, how can I make it so that if user clicks on marksheet button that class should be called & so?
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Oct 25, 2014
Alright.. So I have to make a retail item class that has description, price and quantity. I then have to make a CashRegister class that calculates subtotal, tax, total and displays it (toString). I also have to make a driver class to call the methods from main. I have no clue what I am doing and what I have done does not work. I am trying to make it sort of like a cart, in the CashRegister it should ask the user to enter the description, quantity purchased and the price. Then it would send that to the arraylist of retailitem. I am having trouble using those items in my other methods and then do not know how to call those in the driver class...
So here are my classes: [URL] ....
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Mar 6, 2014
I have multiple Java classes that holds lots of time based parameters, e.g.: (simplified):
Java Code: class Engine {
float rpm;
boolean enabled;
int runningTime;
[code]....
Is there any simply solution to map all these parameters from my TimeRecord to one list(vector,map) of params that user can choose from and see the value in proper form (floating type, boolean type) ?
I just want that user can pick a paremter's name from list or combobox and choose parameter that he wants to see. I don't want to duplicate the data - just some kind of mapping algorithm between list of parameters names and my TimeRecord. eg. some collection class that holds all names and connections: Parameters params; fill combo/list from this class for ( String name : params ) { combo.add(name);}, then when user picks some field from combo: params.getValue( myTimeRecord, name ) return correct parameter value (just my first thought)
Later, I want to replace all floats,ints,booleans with some kind of templated class eg. Value which will hold all kinds of measurement unit with conversion support - but it's only a plan now.
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Nov 1, 2014
I was reading the book, "Head First Java" and it was talking about how there may be multiple classes in a large application, but there will be only one main method.how does it work that way? How can you have multiple classes, but only one main method?
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Jan 16, 2015
I have multiple classes in one package and was wondering how to I use one class while in another?
What I mean is I have one sheet with a class and another sheet with another class. (Separate tabs in Eclipse).
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Sep 12, 2014
I'm trying to create a Java swing chess application, but would like to divide the GUI part of it into at least two different classes (possibly more later, but I'm not sure yet). Currently I have a mainGUI class and a ChessBoard class, both of which extend JFrame. I want the main GUI class to contain a JPanel which will house several components, including a JPanel originating from the chessboard class that contains the actual board.
Is there any way to do this? I tried just creating a ChessBoard object in my main GUI class and then adding it to the component, but I got an illegal argument exception, because apparently you can't add one JFrame to another. How to do what I'm trying to do, or just how to split GUIs into multiple classes in general?
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Apr 25, 2014
i was leaning inheritance and tried to implement it in Java.This is my base class vehicl.java
public class vehicle{
private int topSpeed;
private int cubicCap;
private String modelName;
private boolean hasAlloy;
[code]...
I also have a derived class called car.java.What i wanted to do in the derived class was that i wanted to override the constructor as well as the getInfo() method from the base class.I wanted to add an additional attribute to the car "numberSeats" and display tat too when the object to car class calls the getInfo() method .It showed an error "identifier required" when i tried to compile car.java program.
import java.util.Scanner;
public class car extends vehicle{
//int numberSeats;
//System.out.println("Enter the number of Seats");
Scanner numberSeats=new Scanner(System.in);
numberSeats=numberSeats.nextInt();
//System.out.println(numberSeats.nextInt());
[code]....
explain the errors that i get when i tried to compile car.java without using super keyword or without defining the constructor from the Car class ?
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Feb 20, 2015
What is difference between Java Serialization with Inheritance (IS-A Relationship) and Java Serialization with Aggregation (HAS-A Relationship) ....
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Mar 24, 2015
I'm making a vending machine program to practice inheritance and have a few questions. My superclass is a Soda class, and I'm making subclasses like "Orange soda", "Coke", etc. My first question is, what is the point of the subclass inheriting the instance variables of the superclass? If you have to define them again is there any point in the super class having them? Here is an example of this:
My superclass:
public abstract class Soda {
public double price;
public int numAvailable;
public String name;
public String machineCode;
[code]...
Besides not having to write the vendSoda() method again, what is the benefit of inheritance in a situation like this if you have to define all variables again? My second question is, how could I store all of the code strings from all of the different subclasses in one place? (so when the user enters a code it can search for the code entered to give the desired soda)...
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Jun 23, 2014
On p.176 of EBJ 3 in Action (2nd edition),
MDS don't support all six transaction attributes. MDBs support only REQUIRE or NOT_SUPPORT.... There is no existing transaction to suspend or join when a message is delivered, The two options you have available are REQUIRE if you want a transaction.....
there is no existing transaction when a message is delivered from a queue to an MDB. Why we still need a transaction as it says " REQUIRE if you want a transaction"? When a message is delivered from the queue to the MDB, is this a transaction?
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Mar 3, 2014
I am new at JSF and i want to do some things.
->When the user request for a file that is not exists i want to redirect to a valid url where i can inform him that the file does not exists.
->I am trying to use the properties messages for the language that the user has. I want to use it cause i want to reuse some of the message and it is easier to translate the page to other languages. How when the browser has a default page English to let user change the language to Italian for example but for all page.
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Nov 11, 2014
I am building an application which needs to be able to get the user's location. In JavaScript I would use navigator.geolocation.getCurrentPosition()
Does WebEngine support this function? Obviously it will only work if the device has GPS. I am targeting windows tablets and phones which will have it.
Can I use the webEngine.executeJavascript() to call the javascript if it is supported.
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Jun 18, 2015
When a JavaScript client attempts to open a socket, instead of the connection opening it immediately closes. The client is using:
webSocket = new WebSocket("ws://localhost/example");
The same thing happens for com.sun.net.httpserver.HttpsServer where client is using:
webSocket = new WebSocket("wss://localhost/example");
How can I enable websocket support?
If it's not possible, how can I request for it to be added as a new feature?
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