I am trying to call a constructor from PrepaidCard class in my main method, but I am not sure how to proceed.
As seen below, both the PrepaidCard constructor and the setCardID method have the ability to set the card ID.
public class PrepaidCard
{
public PrepaidCard(String id, int token) {
cardID = id;
tokenBalance = token;
}
public void setCardID(String id, int token) {
cardID = id;
tokenBalance = token;
}
}
Now in this block of code, I can successfully pass the id and token value by calling the setCardID method from the PrepaidCard class. Now I would like to call the PrepaidCard constructor from the PrepaidCard class to pass the id and token value, instead of using the setCardID method.
public class PrepaidCardTest
{
public static void main(String[] args) {
PrepaidCard card2 = new PrepaidCard(id, token);
System.out.print("Enter Card2 cardID: ");
id = input.nextLine();
card2.setCardID(id, token);
}
}
How to call the PrepaidCard constructor from the PrepaidCard class, to successfully pass the id and token value, in my main method?Specifically how to modify or replace this line of code so that it can correctly call the PrepaidCard constructor?
I am getting error in second constructor that I have created, it gives an error: cannot find symbol variable
package Objects;
import javax.swing.JOptionPane; public class Constructor { public static void main(String[] args) { Piggybank1 pg1 = new Piggybank1("Abhinav", 500); pg1.deposit(200); pg1.withdraw(10);
Its written that every constructor calls its super class constructor. And we know, constructors are called to create an object. Does it mean that if I am creating an object of a class, I am actually creating objects of all its super class???
I can call a child method from a main method. If I have a parent called "Assessment", a child called "Quiz", and another child called "test". Can I instinate an object like Assessment a = new test(); and call a method in test.I know the method can be called if I instinate the test t = new test() but that defeats the purpose of inheritance which I'm learning in class.
public class Person{ /*Complete*/ public String format(){ return String.format( "Name: %s", name );
[Code] ....
And I have been asked to add a new field called name, and call the display method in the main. I need to use an appropriate type and privacy for the name field, and once the code is finished, I should see 'Harry Potter' appear on the command line. However I don't know what it means by field. I've tried googling it and one search result said it is a field parameter, and another search result said it was something completely different, and I don't know which one it is. I've created a parameter 'Private String name;' but it only prints out 'name: null'
This is the code I wrote but it obviously doesn't work?
package Practical8;
public class Person{ Private String name; public String format(){ return String.format( "Name: %s", name );
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) == '#'))) {
I have this program, I am wondering if it is possible to call files from the main method and sort them into my saveOneRocord method? If so, how would that look?
I am trying to make a 2d graphical animation using the java swing classes in order to make a frame. I had a basic version working when all of the code was under the main method, but when I moved some into another method it broke it. With y understanding of java my code should work as I create a variable of the method containing the code and then assign the size and exit button. However this causes many problems such as my BeaconFrame method informing me that it is unused when I have used it. Here is my code:
import javax.swing.*; import java.awt.*; public class BelishaBeacon { public void BeaconFrame() { JFrame frame = new JFrame(); JPanel panel1 = new JPanel();
For reference I am programming Java in BlueJ. I am fairly new to the language and I am having trouble with sorting.
I am trying to call / test all of the 5 sorting methods (at the same time) in the main class. To be specific, the sorted list has to technically outputted 5 times.
I figured out how to call / test Quicksort:
Sorting.quickSort(friends, 0, friends.length-1);
But the others are not working correctly. Specifically these:
For reference, this is the output when it is not sorted:
Smith, John 610-555-7384 Barnes, Sarah215-555-3827 Riley, Mark 733-555-2969 Getz, Laura 663-555-3984 Smith, Larry464-555-3489 Phelps, Frank322-555-2284 Grant, Marsha243-555-2837
This is the output when it is sorted:
Barnes, Sarah215-555-3827 Getz, Laura 663-555-3984 Grant, Marsha243-555-2837 Phelps, Frank322-555-2284 Riley, Mark 733-555-2969 Smith, John 610-555-7384 Smith, Larry464-555-3489
This is the class Sorting, which I should note is all correct:
public class Sorting{ /** * Swaps to elements in an array. Used by various sorting algorithms. * * @param data the array in which the elements are swapped * @param index1 the index of the first element to be swapped * @param index2 the index of the second element to be swapped */ private static <T extends Comparable<? super T>> void swap(T[] data, int index1, int index2){ T temp = data[index1]; data[index1] = data[index2];
[Code]...
This is the Main class in which I am supposed to call the sorting methods, SortPhoneList:
public class SortPhoneList{ /** * Creates an array of Contact objects, sorts them, then prints * them. */ public static void main (String[] args){ Contact[] friends = new Contact[7]; friends[0] = new Contact ("John", "Smith", "610-555-7384"); friends[1] = new Contact ("Sarah", "Barnes", "215-555-3827");
public Unit(String code, String name) { enrolStudent(student); this.unitCode = code; this.unitName = name; } public void enrolStudent(Student newStudent){ students = new ArrayList<Student>(); newStudent = new Student(24662496, "Kingsley", " Iwunze"); students.add(newStudent); }
how can I call this enrolStudent() method on this Unit constructor in another class when I create a new Unit. all I need is to enroll students in units when units are created. below is my create unit method.
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();
I was practicing my java skills and came across an exercise in which a non parameter constructor calls a two parameter constructor. I tried a few searches online but they all came back unsuccessful. This is the part I am working on:
public PairOfDice(int val1, int val2) { // Constructor. Creates a pair of dice that // are initially showing the values val1 and val2. die1 = val1; // Assign specified values die2 = val2; // to the instance variables. } public PairOfDice() { // Constructor that calls two parameter constructor }
I tried calling the two constructor using the line "this(val1, val2)" but I get an error because val1 and val2 are local variables.
Then I tried to use the same signature: "this(int val1, int val2)" but that didn't work either.
I'm wonder about the issue of constructor for arrays. Let say I have a class tablica, and one component int[] tab. If I get it right until now tab is nothing more than empty reference to some unexisting array?
import java.util.Random; class tablica{ int[] tab; tablica (){ // i wish it was constructor
[code]....
Then, I'm trying to build the constructor for class tablica. What can be the parameter of such constructor? Is it fields of array? It is simple forf for basic variable
- I liken values defined in constructor with those global defined in class. But how to do it with array component tab.
If I create array object in main method then how can I use this constructor?
public class TestClass { public TestClass(String k){System.out.println(k);} public static void main(String[] args) { try { hello(); } catch(Exception e){System.out.println(e);}
[Code] ....
Explain how to catch block act as constructor with parameter?
"A constructor cannot be abstract, static, final, native, or synchronized."
I understand on why it can't be all of the above, except "final".
Why can't we have a final constructor, i understand constructors are not inherited, hence no chance/case of overriding etc. But why is it not allowed at all ?
So I am working on a school project and I have 2 classes, class FakeGravity contains all the properites and class BouncyBall is my driver class. For some reason when I try writing
FakeGravity gravity = new FakeGravity( );
I get an error. I am attaching an image of the error, and also attaching the program just in case you need more information. Also I was using blueJ to write the program
dcasarrubias, on 27 October 2014 - 02:44 PM, said:
So I am working on a school project and I have 2 classes, class FakeGravity contains all the properites and class BouncyBall is my driver class. For some reason when I try writing
FakeGravity gravity = new FakeGravity( );
I get an error. I am attaching an image of the error, and also attaching the program just in case you need more information.
The LocalStudent class inherits the Student class. The IDE states an error of "no default constructor in Student class".I understand that if a LocalStudent object is created, the default constructor of its superclass (aka Student class) will be called implicitly.there is no LocalStudent object being created, so why is the default constructor of Student being called ?
The default constructor of LocalStudent is also overloaded by the created no-arg constructor containining subjects = null; . So there is no call to the superclass default constructor from the default constructor of LocalStudent.
public class Student { private char year1; public Student(String name, char year){ year1 = year; } public char getYear(){ return year1;
I am trying to create a user defined Exception. I am using a hard-coded value in the constructor of circle class at the time of object creation.But in the constructor this value becomes 0.
import java.lang.Exception; import javax.swing.*; class InvalidRadiusException extends Exception{ private double r; public InvalidRadiusException(double radius){ r = radius;
[Code] ....
Due to this its always generating InvalidRadiusException even if i am supplying a non-zero non-negative value.
I want to be able to check that the data for the ID is limited to a certain collection of characters formatted in a certain. For example, I may wish to limit it to 5 lowercase letters or numbers, or a combination of both. How could I do this?