My current assignment involves me outputting these 2 classes. Yet I'm not really sure in what manner I should go about doing this. I have tried creating a separate class and outputting my toString methods there but for some reason I am getting an error. .
The error message is thus;
Exception in thread "main" java.lang.NullPointerException
at Vehicle.toString(Vehicle.java:91)
at Run.main(Run.java:17)
Process completed.
So I'm working on a project and noticed that my toString() method won't work. This is just an example of the type of code that I have in my real project. THIS IS MY MAIN CLASS
XML Code:
package trialanderror; import java.util.Scanner; public class TrialAndError { public static void main(String[] args) { Scanner keys = new Scanner(System.in); String name; String phonenumber;
Write TestCabAppointment,java class where you will instantiate new CabAppointment objects and read data from RandomAccessFile and create CabAppointment objects and save them in RandomAccessFile You may use FixedLengthStringIO,java class, ICabAppointmentRecord.java interface. Complete the ReadWriteRandomAccessFile.java
How do i print override the toString for WebBrowser as i would like to print out the object bc. Tested the program and it is fine if i put it in the main method rather than the WebBrowser constructor.
import java.util.*; class ListNode <E> { /* data attributes */ private E element; private ListNode <E> next; /* constructors */ public ListNode(E item) { this(item, null);
So I have to write all the methods for a LinkedListQueue. I've got isEmpty, enqueue and dequeue working correctly (I think) but I'm having trouble with the toString method. I tried to do it recursively and it works if there is only one element in the list, but with multiple elements it throws a StackOverflowerror exception. I've tried it multiple different ways, but I can't seem to figure out how to print it out with out clearing everything. We haven't been taught StringBuilder or .append yet, which I saw a lot of as I was looking for solutions, so I can't use those.
public class LinkedQueue<T> { protected LLNode<T> front; // reference to the front of this queue protected LLNode<T> rear; // reference to the rear of this queue private T info; public LinkedQueue() { front = null; rear = null;
[Code] ....
and this is the ITD used with it, for some reason it has the "empty the queue" function as a choice but we weren't assigned that function, so just ignore it.
import java.util.Scanner; public class ITDLinkedQueue { public static void displayMenu() { System.out.println("(1) display menu"); System.out.println("(2) check isEmpty"); System.out.println("(3) enqueue"); System.out.println("(4) dequeue");
Our goal is to write a pretty simple program, one that takes the 12 digit UPC code entered by a user and to not only spit it back out in a format with dashes using toString, and also returns the first digit, a 2 more groups of digits numbering 2-6 and 7-11, and finally display the 12th digit. It then performs an equation to check the last digit and make sure the UPC code is correct.
However, being so new to java (I only learned visual basic before), with this I was introduced to two new concepts that for some reason I simply cannot grasp for the life of me: Using and calling the toString method, and calling on methods that are created in a completely different class file.
The first section of code is my UPC class, which is meant to contain all my methods as well as the toString to be called on:
public class UPC { // Instance variables private int itemType; // digit 1 private int manufacturer; // digits 2,3,4,5,6 private int product; // digits 7,8,9,10,11 private int checkDigit; // digit 12
Write a class encapsulating the concept of a course grade, assuming a course grade has the following attributes: a course name and a letter grade. Include a constructor, the accessor and mutator, and methods toString and equals.Write a client class to test all the methods in your class.
how to test and finish the toString and equals method in this code ?
package labmodule7num57; import java.util.*; public class LabModule7Num57 { // Constructors// private String name; private String letterGrade; public LabModule7Num57 (String name,String letterGrade) {
I need making the toString() method return a String rather than display a message to the screen. Also, I'm not supposed to call the toString method in my demo class to test it, so what should I do instead?
public class cupDispenser { String location; int noOfCups; cupDispenser(String location,int cups) { this.location=location; this.noOfCups=cups; } public String getlocation()
I'm working on a simple 2D Game Framework. Currently it's creating a window, but I'm working on an update method.
I constantly export the framework as a .jar file, and I've added it to the game's build path (using eclipse). I wonder if I can check all classes in the game-project (the project in which I've refecrenced the Framework in) for a specific method (for example update()) and call all found methods with that name from the framework's main class, like this:
public class FrameworkClass1 { private void checkForUpdateMethods() { // Check for update methods on program start } public void update() { runAllFoundUpdateMethods(); // Run all update methods found in the scan } }
I want to do this because it would be a simple way to update and render the game. If the main game-class look something like this:
public class Game { public void update() { // Update the game every time this is ran } }
it will be automatically updated, because it contains a method named update(), instead of naming the main game-class with a specific name etc. It will simply be more flexible that way!
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?
I have been working on a simple problem, but I am stuck. I am trying to learn parent and child classes and how they work. The program in broken into three classes; the DemoBook class that runs the various methods, the Book class that gathers information and displays it, and finally a child class of Book (called TextBook) that just gets one piece of data and then is suppossed to return that data back to Book. However, this is not working and I know I am missing something; I believe it has to do with Set and Get methods, but I am confused with how these work.
Java Code:
public class DemoBook { public static void main (String[] args) { Book aBook = new Book(); Textbook aText = new Textbook();
I have code that displays 3 game scores the series total and average. For some reason game 3 outputs 0 and game 1 and 2 output correctly. I don't see anything different that game 3 is doing that game 1 and game 2 aren't so I'm not sure what the problem is.
java file
package com.valenciaprogrammers.mybowlingscores; import java.text.DateFormat; import java.util.ArrayList; import java.util.Collections; import java.util.Date; public class BowlingScores implements Comparable<BowlingScores>{ private long id;
I have a loop and I was wondering why it is outputting my line twice. Here is the code:
while (x != -1) // closes the program if the user enters -1 for x { System.out.println("Which jar would you like to access? Please select a number between 1 and 3. Press -1 to exit."); x = scan.nextInt(); ourpantry.Selection(x); // tells our pantry class what number the user selected while ((response != "continue")) // loop continues until user gives a valid response
[Code] ....
This results in the Output:
Would you like to spread jam? Y or N. Would you like to spread jam? Y or N.
I created a calendar program so when the user enters a day number and a year it would show the calendar for the year . My issue was that I could not get the numbers to line up neatly and how they should look . Also if its not to much trouble I would like to know how to turn this in to a loop .
import java.util.Scanner; public class Calendar { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.println("Enter a Year"); int Year = scanner.nextInt();
I am currently working towards taking input from the user and storing it in an excel document. However how can I test to make sure that I am trying to save it to an empty cell. Is there some type of method that will check to make sure the cell is empty, otherwise how can this be done?
I was struggling to use BufferedReader to extract some data and then perform some calculations and then have the results as outputs.
I haven't quite solved that issue but in order to progress, I hard coded some values into my application and proceeded with the actual calculation loops etc.
Currently, the value out put from one of my calculations is given as:
1.1704926E7
How can I make the console show it in a natural way. I've performed the calculation manually and it should be 11704926.5 I don't want to lose that .5!
Ideally, it's suppose to print out only Test2, Test3, Test6.. I've tried different combinations of loops and equals() but I never get the correct output.
This is sort of like the last problem I had but it's all about the formatting at the end. I have a file that reads something like:
Name a bunch of text here and perhaps a second or even a third line
I need to output this as:
Name; "a bunch of text here and perhaps a second or even a third line"
Right now I find 'Name' and it outputs:
Namea bunch of text here and perhaps a second or even a third line
How would I add ";" and quotes in the middle? I can imagine that I may need to find name, then skip to the next line and just add name manually as the variable output of the search string.
This is where I am now
public static void main(String[] args) { boolean output=false; String name=""; String junk="CHAMBERS"; TextIO.putln("Search for a name"); name = TextIO.getln(); TextIO.readFile("doc.txt");
[Code] .....
So I'm almost there, but those dange double Names are killing me. I tried to add a bit of code where:
I am Having trouble with my program to validate. It is outputting null into the validation statement then it brings back a run-time error to that validation Statement for the String.
public String validateData () { if (nm == null)nm = "Error! Must enter at least one character"; else nm = name; return name; }//end validation method
Why is this happening, and then once that is completed, why is the validation Sentence in tests Scores not able to validate. I traced it back to out put "Error, a number between 1<100".
public void validateTests () { String testschange; if (test1 < 0 || test1 > 100) { testschange = " You have entered an invalid number, between 1-100. Please restart!"; testschange = Integer.toString( test1 ) ;
At the moment I am studying it and the problem is Taking a range of names in an array and outputting them alphabetically, But for some reason I get an outOfBoundsException. And its starting to get to me. How to put the code in
