Create Method In Main Class And Use It On Object
Feb 26, 2015
I'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.
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Oct 26, 2014
When I try to call an object it can't find the symbol in the argument list. NetBeans says that it cannot find the movieCategory symbol when I try to call it. When I compile it to test a popup comes up that states "One or more projects were compiled with errors. Application you are running may end unexpectedly. I ran it anyways and everything runs up to the point of where it should call the object.
At this point it should get the Movie object and run the code within that, but if I put one of the categories it throws. "Exception in thread "main" java. lang.RuntimeException: Uncompilable source code - Erroneous tree type: <any>at MovieApp.main(MovieApp.java:33)Java Result: 1"
From my understanding to call an object it requires objectName.methodName(argumentList). Here is my Main method
/**
*This application will store a list of 100 movies and display them by category
*/
import java.util.Scanner;
public class MovieApp
{
public static void main(String args[])
{
//Displays <code>String</code> welcome message
System.out.println("Welcome to the Movie Application.");
System.out.println("There are 100 movies in the list.");
System.out.println("What category are you interested in?");
System.out.println();
[code].....
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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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Feb 13, 2014
I am just trying to test this array, for a locker combination program that involves classes...but the array is printing out the whacky numbers for the location. When I try to call the method in the main, it does not work. How do I call a method that exist within a class into the main method?
public class locker {
public static void main(String[] args) {
CombinationLock();
[code]....
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Feb 16, 2014
I have two classes: main (with JFrame) and a panelLogin class with a method returning a panel with all login components..so I create a new panelLogin in main and use the method to get the panel, put it into my JFrame. But here the problem: on the loginPanel the ActionListener for the login-event, if the input is correct,the panel shall disappear and the main panel shall appear.Should I make some kind of top class, which handels the panels?
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Jan 8, 2015
The error I get when I execute my java file.
Exception in thread "main" java.lang.NullPointerExceptionat DogTestDrive.main(DogTestDrive.java:19)
Here is the source
class Dog {
int size;
String name;
void bark () {
if (size < 60) {
System.out.println("Woof woof");
[code]....
Some background: I'm reading "Head first Java 2nd edition" and I'm going through the examples which is showing me how to change the state of an object. The original code looks like the code below, however the previous chapter went over creating array's of an object, so I created an array of the object "Dog" and wanted to re-write it this way. To my understanding, it should work but it's giving me that error when I execute it. The error itself isn't very clear, if I could get a line number pointed to, that would work.
class Dog {
int size;
String name;
void bark() {
if (size > 60) {
System.out.println(“Wooof! Wooof!”);
} else if (size > 14) {
System.out.println(“Ruff! Ruff!”);
} else {
System.out.println(“Yip! Yip!”);
[code]....
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Mar 3, 2014
Im writing a simple program to understand classes and objects. Basically what I have is a file called Program.java where I have my main method.I have another file called Person.java which I want to use to create Person objects. That person can have a name, email adress, phone number, etc.I put both these files in the same folder.in Program.java my first statement is:
Java Code: import Person.java mh_sh_highlight_all('java');
My problem is that when I compile Program.java i get an error message saying that the package Person.java does not exist.So my question is, when you create a class that you want to use for objects, how do you import that class into your class with the main method so that you can use instances of your other class?
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Aug 31, 2014
// Add range to Vehicle.
class Vehicle {
int passengers; // number of passengers
int fuelcap; // fuel capacity in gallons
int mpg; // fuel consumption in miles per gallon
// Display the range.
void range() {
System.out.println("Range is " + fuelcap * mpg);
[Code] ....
I'm compiling it in Eclipse and this continues to show in the console display
Minivan can carry 7. Exception in thread "main" java.lang.NoSuchMethodError: Vehicle.range()V
at AddMeth.main(AddMeth.java:34)
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Apr 22, 2015
How 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.
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Jun 10, 2014
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]....
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Jan 29, 2014
I've written a program just for the sake of it (to learn) and it seem's like theres quite a lot in the main method that perhaps could be split up into seperate classes. I'm not too sure where should start with this though, or what my thought process should have been as I was writing the program.
import java.util.Scanner;
public class Loops {
public static void main(String[] args) {
int answer = 16;
Scanner scan = new Scanner(System.in);
// Question
System.out.println("What is 4 x 4 ?");
[code]...
--- Update ---
here's a version without code comments as they might make it harder to read here -
import java.util.Scanner;
public class Loops {
public static void main(String[] args) {
int answer = 16;
Scanner scan = new Scanner(System.in);
System.out.println("What is 4 x 4 ?");
int userAnswerInt = 0;
[code]...
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Feb 9, 2014
This time I have to make a Black Jack game ( I guess this is a classic) I have created Three classes for this BlackJack( Main), Card, and Player.
What I am trying to do is put the Give one card to the player and remove it from the deck into a separate procedure because I will be doing this several times during the game.
This is the code I have so far Under the class BlackJack.
Java Code:
package black.jack;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;
[Code] .....
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Dec 9, 2014
The following code is located in my main class called InjectionFix. I have another class where I need to call or initiate the string in the code below. How can I achieve this. I tried to create an Object of the class but I cant do this because my other class doesnt contain a main method.How can I get the other class to initiate the code below which is loacted in my main class.
public static String escapeDN(String name) {
StringBuilder sb = new StringBuilder();
// space or # character at the beginning of a string
if ((name.length() > 0) &&
((name.charAt(0) == ' ') ||
(name.charAt(0) == '#'))) {
[Code] .....
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Jan 21, 2014
I saw an example where an (inner)class is declared inside the main method, this is correct or not and why/when it's reasonable to use?so smth like this
public class myClass()
{
public static void myMethod(myInnerClass obj)
{
if (obj.method())
[code]....
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Feb 4, 2015
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]....
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Jul 18, 2014
Why we can't create object of abstract class ,when we can create its constructor?
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Dec 11, 2012
I 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)?
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Oct 5, 2014
Animal 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] ....
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Apr 16, 2014
I'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).
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May 20, 2015
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] ......
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Nov 3, 2014
How should I call my findSmallest method in the main class.. Here is the code:
public class Tester {
public static void main(String[] args){
try {
BinaryTree<Integer> myTree2 = new BinaryTree<Integer>();
myTree2.insert(5);
myTree2.insert(2);
myTree2.insert(7);
[Code] ....
So the question is what kind of parameter I should pass in myTree2.findSmallest()??? Here is my findSmallest method..
public E findSmallest(Node<E> parent){
if(parent.left.left == null){
E returnValue = parent.left.data;
parent.left = parent.left.right;
return returnValue;
} else {
return findSmallest(parent.left);
}
}
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Aug 9, 2014
Essentially, 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.
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Mar 8, 2015
I 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?
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Nov 1, 2005
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 {}
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Oct 27, 2014
I 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
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May 5, 2014
I am attempting to override the equals method from the Object class which checks if two variables point towards the same object. I want the method to check if if the argument being passed in(an object) has the same data(instance variables) as the object that's calling this method. A NullPointerException is being thrown; Here is the code.
package javaapplication5;
import java.text.NumberFormat;
import java.util.Scanner;
import java.lang.Object;
public class Product {
private String product;
private String description;
private double price;
[Code] ....
And here is the stack trace
Exception in thread "main" java.lang.NullPointerException
at javaapplication5.Product.equals(Product.java:42)
at javaapplication5.Product.main(Product.java:24)
Java Result: 1
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