Passing Values Into Constructors Using Main Or Static Method Functionality
Jan 24, 2014
I just kinda get stuck when it comes to passing values into constructors, using main method or static method functionality. In theory i kind of understand how it work but when i type it, it's totally different! I have to have a junit test too but i guess i could do that in the end.
I have attached the assignment. So, how to proceed with this:
public class Flight {
int flight_number, capacity, number_of_seats_left;
String origin, destination;
String departure_time;
double original_price;
[Code] ....
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Oct 1, 2014
in java why main method is always static in nature...
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Jan 7, 2014
What does void and static mean in the main method?
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Dec 3, 2014
I believe I am on the right track but when I run the program I get an error that the class that I can't call on the method. I need to have what is selected in the JCheckBoxes added to the toppings array and I can't get that done what so ever.
Java Code:
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
public class PizzaOrderListener
{
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
[Code] ....
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Mar 20, 2014
We are learning about how to pass objects into constructors. In our class, we made this following code:
public class InventoryItem {
//fields
private String description;
private int units;
//Add New constructor
public InventoryItem(InventoryItem some_object) {
description=some_object.description;
[Code] .....
As you can see the object of the same class is passed as the argument. Inside the constructor, our teacher did
some_object.description
This constructor, from my understanding, copies the description field and unit field to an object to the new object of class. Meanwhile, here is the demo class.
public static void main(String[] args)
{
//Create object
InventoryItem item1;
item1=new InventoryItem("hammer",20);
System.out.println("Item 1: ");
[Code] .....
Over here, my teacher uses :
.getDescription
My problem is that in the constructor of the first class I showed, why didn't he use
.getDescription
method instead of this
.description
May I know what is difference between these two. If I use .getdescription that would return the value of a field from that object too.
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Sep 28, 2014
I am doing an assignment and I am clueless as to what I did wrong or supposed to do in terms of placement of coding.
This is what I supposed to do:
1.) Type the following shell for the class:
public class ParadiseInfo
{
}
2.) Between curly braces of the class, indent a few spaces and create the shell for the main() method:
public static void main(String[] args)
{
}
3.) Between the braces of the main()Method, insert a call to the displayInfo() method:
displayInfo();
4.) Place the displayInfo() method outside of the main() method, just before the closing curly brace for the ParadiseInfo class:
public static void displayInfo()
{
system.out.println ("Paradise Day Spa wants to pamper you.");
system.out.println ("We will make you look good.");
}
This is what I attempted to do:
I know it is wrong I am just clueless on where to put the code and why
public class ParadiseInfo
{
displayInfo();
public static void main(String[] args)
{
public static void displayInfo();
}
system.out.println("Paradise Day Spa wants to pamper you.");
system.out.println("We will make you look good.");
}
--- Update ---
I also tried it this one and ended up with 1 error..
public class ParadiseInfo
{
displayInfo();
public static void main(String[] args)
{
}
public static void displayInfo();
{
system.out.println("Paradise Day Spa wants to pamper you.");
system.out.println("We will make you look good.");
}
}
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Jan 8, 2014
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
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Aug 27, 2014
For the below program what are the default values passed by the JVM in order to call main() method
class program
{
public static void main(String[] args)
{
System.out.println(args[0]);
System.out.println(args[1]);
}
}
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Oct 21, 2014
package Experimentation;
import javax.swing.*;
import java.awt.event.*;
public class SimpleGUI1B implements ActionListener {
JButton button;
public static void main(String[] args) {
SimpleGUI1B gui = new SimpleGUI1B();
gui.go();
[code]...
This is a program from Head First Java! since main is static it shouldn't be able to call non-static methods because statics do not use any instance variable values but in the above program we're call a non-static method go() how is it possible?
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Oct 2, 2014
Java Code:
public class Puppy{
int puppyAge;
public Puppy(String name){
// This constructor has one parameter, name.
System.out.println("Passed Name is :" + name );
}
public void setAge( int age ){
puppyAge = age;
[Code] ....
How do I put 3 values of the each variable without replacing the last inputted one?
Like when I input "Tommy" and input another name "Gerald", "Tommy" won't be replaced by "Gerald" when I input again.
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Mar 26, 2015
This is my code inside the method:
@Post
public static String getDetails(Representation entity) throws Exception {
String customerId = getQuery().getValues("cus_id");
}
I use this code in Restlet Representation. I try to get the value from the Request API. But I am facing the problem as "Cannot make a static reference to the non-static method getQuery() from the type Resource".
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Jun 27, 2014
From what i understand static methods should be called without creating an instance of the same class . If so why would they return an instance of the same class like in the following : public static Location locateLargest(double[][] a) , the Location class being the same class where the method is defined . I don't understand this , does it mean that every field and every method in the class must be static ? Meaning that you cannot have instances of the class because everything is static . Or it's just a mistake and the class Location cannot have a static method: public static Location locateLargest(double[][] a) ?
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Apr 26, 2015
I can't figure out what this error message "Cannot make a static reference to the non-static method getEndUserCharge(long, long, long, long) from the type UpdateUserWS" actually means.
The error is coming from:
public void updateDetailsPackage() {
some unrelated code
long zero=0;
double endUserCharge=0;
endUserCharge = UpdateUserWS.getEndUserCharge(long zero, long zero, long zero, long zero); <-------- error is here
[Code] ....
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May 26, 2015
Alright, I have two classes, this one
public class Player {
private String player;
public String getPlayer() {
return player;
}
private int strength;
private int defense;
[Code] .....
However, it says that under Player.getPlayer() that it 'Cannot make a static reference to the non-static method'.
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Oct 28, 2014
Why I can create an Instance of a class that contains non static variables within the static main method ?
This program runs fine
import java.util.*;
public class Test{
public int j;
public static void main(String[] args) {
Test test1=new Test();
System.out.println(test1.j);
[Code] .....
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Jul 27, 2014
I'm working on a banking program that is supposed to use 3 classes (Account-base class, CheckingAccount, and SavingsAccount) and several methods to display the banking information (ID, balance after a withdrawal and deposit, and the annual interest rate). This should be a pretty simple program, but I'm getting hung up on one portion of it. I'm getting some compiler errors, all of which deal with non-static variables being called from a static context (I'll also post these errors following the code). Up until the middle of last week, we just declared everything as static, but that's changed and I'm having trouble figuring out when to and when not to use static when declaring my methods, hence the compiler errors.
import java.util.Date;
public class Account {
private int id = 0;
private double balance = 0;
private double annualInterestRate = 0;
private Date dateCreated = new Date();
[Code] ....
Here are the compiler errors I am receiving:
Compilation completed. The following files were not compiled:
6 errors found:
File: C:UsersHiTechRedneckDesktopSummer II 2014Computer Programming PrincipleProgram 5CheckingAccount.java [line: 7]
Error: non-static method getId() cannot be referenced from a static context
[Code] .....
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Nov 18, 2014
I had a TestColor class which contained methods to change hue, saturation, brightness, red, green, blue of TestColor's instances but also had static methods which take in an additional parameter for an instance of TestColor and returns the affected instance of TestColor. Now instead of having one method for every possible color effect to be applied to an image, how can I have one method that takes in an Image parameter, a static or non-static method reference from TestColor parameter and lastly an intensnity value parameter. This is so that I can make an affectedImage object instance inside the method and a Graphics2D object for drawing to each pixel of the new image, now I have one for loop and one nested for loop for the x and y pixels of width and height of the old image and inside the nested for loop I'd create a TestColor by calling getRGB on the image's pixel. Then I would apply the static or non-static method reference somehow to change the color with the intensnity value and after applying it draw to the new Image with Graphics2D. How to would I parametize a method reference and be able to use it in such way?
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Jul 14, 2014
One class having two method one as static n another as non-static, 2 threads are there t1 is accessing the static method and t2 the non-static method is it possible n both are sharing the same object.
I now we have two kinds of lock one is object level lock and another is class level lock
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Feb 1, 2015
I am trying to compile the following code where the entry point is Main.java but i am getting the following error "Error non-static method add(int[]) cannot be referenced from a static context in Java " ....
If i add the keyword static in add method of A.java it works properly......
Class Main.java code
package com.company;
public class Main {
public int [] a= new int[]{1,2,3};
public static void main(String[] args) {
Main n= new Main();
[Code]...
Both the classes are in same package
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Oct 3, 2014
I have written a small program that creates a loop that only fails to continue once we reach a StackOverflowError exception. It looks just like:
class MyFirstApp {
static int counter;
public static void main(String[] args) {
counter++;
System.out.println(counter + " in main.");
roundAbout();
}
public static void roundAbout() {
counter++;
System.out.println(counter + " in roundAbout.");
main( new String[0] );
}
}
The idea of the program is to go between each method without using an object. Each time the method is entered the static int counter variable is incremented and outputted along with its respective loop. The loop does, however, fail eventually.
By calling the between the methods we build a tower of stack frames that eventually topples. The number of times this runs before the StackOverflowError occurs varies, though. Sometimes I get 6553, 6554 or something else close to these values.
Is there a way to pop a method of the stack or clear part of the stack so I can keep this going? I don't know where I would use this but it would be nice to know.
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Oct 6, 2014
class Test
{
static Test ref;
String[] arguments;
public void func(String[] args)
{
ref.arguments = args;
[code]...
This code run perfectly.But the static method is acessing a non static method which was supposed to be not possible.
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Jun 24, 2014
We know that a non static method can not be directly refrenced from static method but in the example given below there is no such error.Why?
class A
{
private void display()
{
System.out.println("In A");
}
public static void invoke (A x)
{
x.display();
[code]....
In above case a non static method display() is being invoked from static method invoke ()but it is not giving error.why?
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Sep 8, 2013
Which is more efficient static block or static method ?
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Mar 1, 2015
I am trying to pass the values for UPPER_BOUND and LOWER_BOUND from the main method into the getValidNumber method. However, I'm not sure how to do this. The rest of the code is correct as far as I know, I just need to get the values for the bounds into the getValidNumber method. How would I do this? the notes in the main method explain what I need to do.
public static void main(String[] args) throws FileNotFoundException {
Scanner kb = new Scanner (System.in);
final double LOWER_BOUND = 0;
final double UPPER_BOUND = 100;
//Call the getValidNumber method, passing it the values LOWER_BOUND and UPPER_BOUND.
//Take the returned value and store it in a variable called num.
//Print out the value of num (here in the main method)
[Code] .....
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Feb 19, 2015
I am trying to get the username and password for one class and send them to another. However I cannot send them in the constructor because a database class is getting them and I need that constructor blank. However if I do not pass the class in the constructor I get a NULL error, even better when I do pass it in I seem to get a thread lock. I do try to do my own housekeeping and close the one frame before I open a new one but it doesn't work. I will do my best to show the design of the program.
program starts
Java Code: public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
// connects to database and generates a GUI
new UserPromptScreen();
[code]....
I have to pass in UserPromptScreen in for it to work. This will cause me issues later with my design.
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Apr 30, 2014
I'm supposed to write a program that reads in 20 numbers stores them into a one dimensional array and then create a method that will calculate the average of the numbers in a separate method.
I've written a for loop in the main method that will take in the numbers but now I need to know how I can pass those values to a method that will calculate the average.
public class ConstructorHomework {
private static double average; //Declaring the Global Variable
//This Method Calculates The Average
public void avg(int x){
average = x/20;
[Code] .....
This is the main method an it contains the for loop that will take in 20 numbers
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
final int size = 20;
double[] array = new double[size];
for (int i = 0; i < array.length; i++){
array[i] = input.nextDouble();
}
//
Here I was trying to create and object and use it to pass value to the method
ConstructorHomework a = new ConstructorHomework();
a.avg(); //Problem is that I don't know what to put in the brackets
a.showNum();
}
}
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