Name Given To Two Or More Methods In Class With Same Name But Different Parameter / Argument Lists?
May 9, 2014What is the name given to two (2) or more methods in a class with the same name but different parameter/ argument lists?
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Passing Object Argument To A Method - Unable To Call Methods On Argument
Feb 7, 2015I am trying to pass an object of type Product p to my editProduct method, however trying to call p.getName(); doesn't work and throws a NullPointerException. The same kind of thing works for my displayRecord method (in a different class) and I can call .getName() on Product p, also passed as an argument to that method. Below is my editProduct class. The NullPointerExcepion is being thrown at line 61 (i.e., nameField.setText(p.getName());).
I don't know if I explained right, so here's a line thing of how the classes relate:
Search >>>(field.getText())>>> displayRecord(Product p) >>>editProduct(p)>>> EditProduct
And as a side note: adding the line p = new Product(); fixes it and successfully runs the class (including the Save and Quit parts) but obviously I want it to specifically refer to the Product I pass to the method.
Java Code:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.util.ArrayList;
import javax.swing.BorderFactory;
[Code] ....
I'm asking a question because I don't understand how Product p could possibly be null, because the argument is passed through my DisplayRecord class, which also takes a Product p argument and works. In that class, I have declared Product prod = p; and prod is what I am passing to editProduct.
Array Lists In A Class
Dec 6, 2014What is going on here in the main class is a zoo that requires information to be read from and saved to a .txt file. I have made three arrayLists for each .txt file, I am getting errors for illegal start to an expression
import java.io.*;
import java.util.*;
public class ColumbusZoo
{
public static void addHelper(ArrayList<DomesticAnimal> a){
Scanner s = new Scanner(System.in);
System.out.println("What species");
[code].....
Parent Class - No Argument Constructors
Mar 10, 2014class Test3 {
} class MySub extends Test3 {
}
class Test4{
public static void main(String args[]) {
MySub m = new MySub();
}
}
I learned that if a class and its parent class both have no constructors, the compiler is supposed to complain. When I compiled Test4, i got no errors. why did it give no errors?
I read this article : [URL] ....
Sorting Lists In Employee Class
Feb 5, 2014A Employee Class where i want to sort there lists one by there salary and one by there name individually as per the requirement ? How we do it?
View Replies View RelatedRename To Functions And Lists Class File?
May 29, 2014What are they the rename To functions and lists the class file?
View Replies View RelatedEnum Class Throwing Illegal Argument Exception?
Mar 4, 2015I have a enum class which contains some string which i am comparing to a string i get from a user
Java Code:
public enum Compare {
a, b, c, d, e, f
} class SomeClass {
String method(String letter){
Compare word= Compare.valueOf(letter);
}
} mh_sh_highlight_all('java');
Everything works fine but when I added a new word to it like "g" it throws the IllegalArgumentException ?
Declaring Methods For A Class In Its Own Class Whilst Objects Of Class Declared Elsewhere?
Mar 5, 2015How 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?
How Is Class Cast In Method Parameter
Jan 15, 2014how is cast a class at a methods parameters? i have a problems in a methods paramter. i draw red line my exception and mymethods is orage color ....
Caffe drink = new Caffe();
CoffeCup cup = new CoffeCup();
cup.setTempeture(100);
drink.drinkcaffe((CaffeCup)(cup.getTempeture()));
[code]....
Inheritance In Java - Child Class Get Copy Of Methods And Variables Of Parent Class?
Mar 1, 2015Does 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 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 Get Access To The Method With A Parameter Of Class Type Variable
Feb 19, 2014how to get an access to the method with a parameter of class type variable, lets say: public void insert(Record newRecord, int pos)?
View Replies View RelatedMethods From Original Class Receiving Error When In Test Class
Jul 5, 2014I am working on a program that simulates a bug moving along a horizontal line, My code works correctly when I test it in it's own class but when I tried testing my constructor and methods in a test class I received an error saying, "package stinkBug does not exist" on lines with my methods. However, stinkbug is not a package.
Java Code:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
[code]....
Creating WordCounter Class With A Constructor That Takes File Name As Parameter
Mar 4, 2014Instructions
Create a WordCounter class with a constructor that takes a file name as a parameter
The class should have two fields: one for the file name and one for a HashMap to store word count information
The constructor should call a private method, countWords, that reads in the file and counts the word frequencies
The class should contain a get method for each field, as well as a print method that prints out the map in the following format:word:frequency
When printing, the map should be sorted by either the word order or frequency (Hint: see Collections.sort)
You should include the sample text file on Blackboard. This is what i got so far
Java Code:
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Scanner;
public class WordCounter
[Code] ....
Write A Class Named Calculator Add Four Methods To That Class
Jan 30, 2014Write a class named Calculator add four methods to that class:
add(int a, int b)
sub(int a, int b)
mul(int a, int b)
div(int a, int b)
Then write a Tester class with main function and show the use of the methods in Calculator class..
Passing Parameter From Object Of Class B To Object Of Class C By Use Of Class A?
Dec 13, 2014Assuming 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 Replies View RelatedMethods In Object Class
Jan 16, 2014We 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 RelatedMultiple Methods In One Class
Sep 13, 2014Is it possible to have multiple methods in one class?And can I use the Scanner in methods other than the main method?
View Replies View RelatedMove A Methods To A New Class
Feb 5, 2015there are two classes here. I need to put the max and min methods should be in the tester class, but I have tried moving it to the tester class and it will not comply. When I run I get a list of errors of "Error:(43, 9) java: illegal start of expression
Error:(43, 16) java: illegal start of expression
Error:(43, 22) java: ';' expected
Error:(43, 41) java: '.class' expected
Error:(43, 52) java: illegal start of expression
Error:(43, 51) java: not a statement
Error:(43, 53) java: ';' expected
Error:(57, 9) java: illegal start of expression
Error:(57, 16) java: illegal start of expression
Error:(57, 22) java: ';' expected
Error:(57, 41) java: '.class' expected
Error:(57, 52) java: illegal start of expression
Error:(57, 51) java: not a statement
Error:(57, 53) java: ';' expected"
package A808;
public class FuleTesterV1
{
public static void main(String[] args)
{
String titleLines;
titleLines = "Yearly Gas Mi Calc | Assignment 8.08";
String TitleLines;
TitleLines = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~";
[code]....
How Many Methods Should Be Included In Class Definition
Apr 6, 2014Suppose you have an abstract class say Sparrow that extends the abstract Bird class. The abstract Bird class has the abstract methods, fly() and run()
How many methods from the Bird class should you implement in the Sparrow class?
Override Certain Methods In Class File?
Oct 16, 2014I am wanting to override certain methods in some Minecraft class files, and tell those class files to use code from my class files.
And no, I don't mean extend a class. When I try to extend from the main Block.Class, it makes that file as another block file for the game, or something.
So like, I want to tell the main file that handles block registries to use the code from my class file to register my custom blocks to the list of blocks, but without modifying that main block file.
Is this even something that's possible?
Also, I know that the way a file is named affects the loading order. My class files would be named using symbols to make it load right before the class file I want to override.
Scanner Class - Can't Seem To Access Methods
May 9, 2014I have two classes built for this assignment. One with getters, setters and constructor and a test class. The test class works fine up until the point when the user wants to (M)odify an employee that he/she built with the loadEmployee method. What happens is I need to enter multiple "M" inputs before anything pops up, and when something pops up, it's the displayMenu instead of modifyEmployee method. I imagine it has something to do with the amount of sc.nextLine()
import java.util.Scanner; // utilize scanner via console
import java.text.NumberFormat; // allows numbers to be format in form of currency
//Example of "big loop" in main to repeat using a No Trip (0,N) test first
public class EmployeeTest {
// space provided to make code easier on eyes...
[code]...
Create Instance Of Own Triangle Class And Use One Of Its Methods
Mar 15, 2014So in the code below I create an instance of my own triangle class and use one of its methods. The thing is I use one of my triangle classes methods in a method other the main method of my main program so I'm thinking it can't access it?
Any way here's the code for my triangle class
import java.util.Scanner;
public class QudratullahMommandi_Triangle_06 {
Scanner keyboard = new Scanner(System.in);
private double side1;
private double side2;
private double side3;
[Code] ....
and here's the error message
QudratullahMommandi_S_06.java:46: error: cannot find symbol
{ triangle1.outPut();
^
symbol: variable triangle1
location: class QudratullahMommandi_S_06
1 error
Using Accessor Methods To Access Data From Another Class
May 6, 2014I have been asked to write a program with 3 classes(an interface, a store and a product class) and I have been going ok until I need to display data on the interface that is held in the product class. At the moment the code will compile fine but when I run the program and try to use the writeOutput() method I get a stack overflow error.
I realise now that it is because of a non-terminating recursive call, however I can not think of a solution on how to fix the problem. And just to clarify, what I am aiming to do is have the MatesTerminal class display the data for name that is stored in the Product class(I have no way of determining which product to display at this time, so I would like to be able to display the data for all three products if possible). Anyway this is what I have so far:
The method from the MatesTerminal Class:
private void writeOutput() {
int productChoice;
Scanner console = new Scanner(System.in);
[Code].....
Creating Methods Using Arrays - Fraction Class
Sep 27, 2014I am trying to get the average of 3 different fraction arrays. I made a fraction class and I made methods such as read() and average() in this new class.
package fractions;
import java.util.Scanner;
import java.util.Arrays;
public class FractionArrays {
public static void main(String[] args) {
Fraction completeFraction = new Fraction(5,6);
[Code] ....
I was wondering if there was any way to use the arrays I created in the read method in the average method. If I find that out I should be able to do it on my own. Is there a way to make the arrays public to use in different methods?
Creating Instance Methods And Driver Class
May 5, 2014Okay, so I have to create a class with instance data and instance methods.
First, BankAccount class. It should contain the following information, stored in instance variables:
First name: The customer's first name.
Last name: The customer's last name
Balance: The amount of money the customer has in the account.
It should have the following methods:
BankAccount(String firstName, String lastName,
double openingBalance)
This constructor creates a new BankAccount
public String firstName()
Returns the customer's first name
public String lastName()
Returns the customer's last name
public double balance()
Returns the customer's account balance
Finally I need to create a driver to test my class. And create several accounts and verify that the first name, last name, and balance methods work properly. This is my code below.. I don't know if I did it right.
public class BankAccount {
String firstName, lastName;
double balance;
public BankAccount(String firstName, String lastName, double balance) {
[Code] .....