Stuck On Adding Entries Method
Apr 13, 2014
I think I'm about 90% complete with this program but I'm stuck on my adding entries method. It gives me a runtime error which says:
Enter the name:
Bill
Exception in thread "main" java.lang.NullPointerException
at Phonebook.addEntry(Phonebook.java:70)
at Phonebook.main(Phonebook.java:49)
Here is my code:
/*
* This program asks the user for input for a name, phone number and notes up
* to 200 entries. It stores every contact in a file. Type 'h' for help while
* running this program.
*/
import java.util.Scanner;
import java.io.*;
[code]....
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Jul 19, 2014
Basically I have a class called Book. Its supposed to have a few simple methods that set the title of the book, mark it as returned or borrowed. So specifically my problem lies in the implementation of the method that decides if the book isBorrowed. I was thinking i'd use a simple if/else statement but the way i've been trying hasn't been successful. This is what i've tried so far.
public class Book {
String title;
boolean borrowed;
boolean returned;
boolean isBorrowed;
// Creates a new Book
public Book(String bookTitle) {
[Code] .....
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Nov 13, 2014
My issue is that when I run my search, it does find a goal. However, when I try and print the route using my print route method, it just gets stuck in a loop of printing the same two nodes. What is wrong with My A* implementation?
package search;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
[code]....
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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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Sep 7, 2014
I am very confused about why my code is not working.. The function of my code will add records in my database (MySQL), Swing components of my frame..
btnUserAdd = jButton
txtUname, txtPword, txtLname, txtFname, txtMname, txtEmpNo = jTextField
cbAccType = jComboBox
EmpNo, Uname, Pword, Lname, Fname, Mname, AccType = MySQL fields
I created a method to be called when btnUserAdd is clicked. here is the code for the method:
public void UserAdd(){
String sql = "SELECT * FROM User WHERE Uname = ? and EmpNo = ?";
try {
pst = conn.prepareStatement(sql);
[Code] ....
the error is that it does not add the record it will display JAVA.LANG.NULLPOINTEREXCEPTION...
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Jan 17, 2014
im new to java and i wanna make a program using java that can add order entries for a restaurant but how to... i was hoping something that would ask to person to input one or two items and before it calculates the total amount to be paid it will ask the guy who inputs the amount whether or not there are additional orders or not before it prints out the total amount... I am pretty sure it will need an if-else statement..
import javax.swing.*;
import java.util.Scanner;
public class OrderCalc {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame aFrame = new JFrame("OrderCalc");
aFrame.setSize(500,250);
aFrame.setVisible(true);
[code]....
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Nov 15, 2014
I have a web form with a field Department. I want to add Sub Departments(unknown number) of one Department and then further Sub Sub Departments(unknown number) of one Sub Department. How I will make a form and how I will add this data in attached database. I have one solution:
One Department field with a button to add any sub department if any. By clicking on button, a new row will be generated with another text field and new button. In this way, it will go on. Tree like structure.
But I have another solution, JSF Tree to add or delete entries on the run time. But the problem is that I am unable to find any example of JSF tree like structure populated from database and in which we can add or delete entries on run time and on the same time these entries may also be stored in database.
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May 13, 2013
I am writing a program in the GUI Builder and found that when I add code to print user input from text fields to a text file, the main method is no longer recognized. It throws all kinds of errors.
I have been able to get the code to work separately in a project file. Also, have been able to print to the console.
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Aug 6, 2014
I have a database of peoples names linked up to a from to enter a new employee.The form has a previous and next button that should cycle through the employees alphabetically.What im doing the cycle by now is ID which isnt in alphabetical order and just goes by the order they where entered in.
Is there any way to cycle through alphabetically instead? Is running a query each time the next/previous button is pressed the correct way or should it just grab all the names in the array. Theres probably 150 names.
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Jul 8, 2014
I have an editable JTable that has a lot of JComboBox's as cell entries. I would like to be able to "arrow over" to said cell, and with a pressing of either a numerical button or by typing the first letter of the String selection (possibly followed by a second), be able to select the appropriate selection from the cell's JComboBox. I have tried to add a key listener to the JComboBox itself, which works given that I click on said cell and show its menu.
How would I go about ensuring that, when focus is on the cell itself, and I start typing, the appropriate selection is chosen?? (I think this might get into key binding, but I don't know if I have to try it from the scope of JTable, or from that JTable's TableModel (which I have made my custom version of).
Here is what I have so far (everything but SandwichNumber, SandwichName, and Oregano uses JComboBox): [URL] ...., how would I do such key binding?
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Mar 9, 2014
Assignment: Develop a GUI-based program to read the entries of a matrix from a text file. The first number is the number of rows; the second number is the number of columns. The remaining numbers are integers between 1 and 9 in row by row order. Scan the matrix, highlight (display the entries in different color) all cells that form a group of five cells with the same value horizontally, vertically or diagonally.
Example of text(.txt) file:
7 7
3623161
3666669
3936293
3594955
3289867
2493998
1399998
Example of output:
3623161
3666669
3936293
3594955
3289867
2493998
1399998
* ^^this would be what it would look like when displayed in the GUI. But it would be colored. Anything that has 5 in a row ...My Class File:
// GUI-related imports
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Scanner;
// File-related imports
[code]....
EX.
0=black(when there is no combo. of 5)1=blue(horizantal combo of 5)2=red(vertical combo of 5)3=green(right diagnol combo of 5)4=purple(left diagol combo of 5)
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Jun 22, 2014
I have a program for a phone directory. It needs to add, delete, append, and edit telephone records. I've gotten it to write and search the files. Just need to get it to delete and edit them.
Here's what I have so far:
import java.nio.file.*;
import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
import static java.nio.file.StandardOpenOption.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
[code]....
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Dec 7, 2014
I have a 2d array that i am manipulating. In my class i have a constructor that takes the dimensions of the array and within th econstructor i need to randomly fill the array. However, when i try to manipulate it in the test program, all that prints out are the default values.
here is the class
import java.util.*;
import java.lang.Math;
import java.util.Arrays;
import java.util.Random;
class SummerStats
[Code] .....
And here is the printout
Enter number of rows(people):
3
Enter number of columns(years):
3
Enter number of person to find sum salary:
1
Enter year to find Max salary of that year:
1
[]
[]
The max salary is at index: (0, 0, )
The largest salary ocurred in year: 0
The sum of person 1 is: 0.0
The total of all salaries is: $0.0
The max salary in year 1 is: 0.0
The average salaries for each year:
0.0, 0.0, 0.0,
The total salary for each person is recorded below.
And the last method called doesn't finish or printout ie the program doesnt end
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Aug 15, 2014
I have a problem with this application , I have a button that allows users to delete entry's from the array list, but i've noticed when i go back and click display entry's the correct entry has not been deleted.....for example if i enter a,1,2 then b,1,2, then c,1,2 in fields, then delete c,1,2 when i actually go to display the data entered a,1,2 will be gone not the one i entered.
So it seems to be deleting the entry at index 0 of the array list no matter what and not the chosen item..Delete Button Code
private void deleteBtnActionPerformed(java.awt.event.ActionEvent evt)
{
if (numTf.getText().equals("") || nameTf.getText().equals("") || yearTf.getText().equals(""))
{
JOptionPane.showMessageDialog(null, "All fields must be full");
}
else if (count == 0)
[code]....
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May 5, 2014
This program contains a superclass and a subclass that will gather the following information from the user:
name, address, phone number, and customer number.
Everything works fine except that I have to create a boolean method in this program that is required to determine based on user input whether they want to be added to a mailing list.
I cannot get this method to work with main, each time it is called it will always return the value but main will constantly read the last statement (else, where it will read "not wanting to be added to the mailing list).
The only way I can get this part of the program to work is by adding an equals method in main that ignores the case, but I am required to write a boolean method so this is not allowed.
Superclass:
public class Person
{
private String name;
private String address;
private String phoneNum;
public Person(String pName, String add, String number)
{
name = pName;
address = add;
[Code] ...
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Feb 18, 2015
I am using the following code to create a dialog , but my need is user can select only 1 entry . Using this code
can select multiple items by pressing Ctrl ... How it can avoid ... My current code is
Java Code:
SecureCloudStorage_Service service = new SecureCloudStorage_Service();
List<String> files = service.getSecureCloudStoragePort().listFiles();
SelectFileDialog dialog = new SelectFileDialog(this.getFrame(),true,files);
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
int x = (screenSize.width - dialog.getWidth()) / 2;
int y = (screenSize.height - dialog.getHeight()) / 2;
dialog.setLocation(x, y);
dialog.setVisible(true); mh_sh_highlight_all('java');
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Feb 19, 2014
Write an interface Directory to manipulate entries in a telephone directory for the University. The interface must support the following operations:
1) The ability to insert new entries into the directory. Entries should be stored in alphabetical order of surname.
2) Delete entries from the directory either by name or number
3) Provide a lookup method that will find the extension no of a member of staff given his/her name. You should try to make this method run as efficiently as possible.
4) Change a person's telephone number
5) Print the telephone directory in a neatly tabulated fashion.
Write a class ArrayDirectory that implements this interface using an array to store the telephone directory information. The class must store the surname and initial for each member of staff and their telephone extension (a four digit number which may start with a zero). You may find it useful to define a class Entry to store information about individual entries. The entries should be read into the array from a text file consisting of multiple lines in the following format:
Surname<tab>Initials<tab>Telephone extension
Write a main program that reads in data from a file and then tests all the methods of your class interface. Note it is not necessary to write data back to disk (even if it has changed) in this project.
For data insertion and lookup, you should measure the performance for the average case (e.g. looking up a record in the middle of the data). To do this you can use the static method System.currentTimeMillis() which returns the time in milliseconds. To get an accurate measure of the time to perform an operation it is a good idea to perform each operation 1000 (or even 10000) times and measure the time taken. This will remove any problems due to the system clock having a coarse granularity (not ticking very often). Make sure you only time the method and not any input/output associated with it. Your documentation should include a discussion of these results.
Part 2
You decide that your solution to part 1 may be too slow to be useful when used with a real large telephone directory and make the following changes to attempt to improve the performance of your program:
1). Provide a second implementation (ListDirectory) of the Directory interface using the Java Collections List interface and LinkedList classes.
2). The changes in 1) should make adding, deleting and modifying records more efficientbut will probably reduce the time to lookup numbers. To overcome this you use a technique called hashing. Instead of storing all the records on one list you use a series of lists. The data for all people whose surname begins with "A" is stored on the first list, records for all people whose surname begins with "B" on a second list and so on. Write a third implementation (HashDirectory) of the Directory interface using this technique.
Again, you should measure the performance for the best, worst and average cases of implementations 1) and 2) above. Compare the efficiency of each of the 3 implementations in your documentation.
Part 3
Choose one of your 3 implementations from Parts 1 and 2 and embed it in a graphical user interface that allows users to perform all the methods in the Directory interface using a mouse and keyboard appropriately.
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May 18, 2014
I'm doing a project in netbeans. I have to make a on-line bank with all the GUI. In the middle i got stuck with the classcastexception..
public class Banca {
public static void main(String[] args) throws IOException, ClassNotFoundException {
// dati dei clienti
Anagrafica c = new Anagrafica();
[code]...
And here's the class of the activities of an account.. I'm not posting my classes Conto( Bankaccount) & Movimento (Activity) because those two already do what they should..
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Mar 16, 2014
I'm trying to do the following and my code is putting me in a loop and not allowing me to input a valid entry after using an invalid #.I ask the user for input which contains a loop if the user doesnt use the correct information, however the loop doesnt allow the user to input if the entry fails the which statement
import javax.swing.JOptionPane; // Needed for JOptionPane class
public class LoanQualifier
{
public static void main(String[] args)
{
double salary; // Annual salary
double yearsOnJob; // Years at current job
String input; // To hold string input
// Get the user's annual salary.
input = JOptionPane.showInputDialog("Enter your " +
[code]....
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Oct 6, 2014
I have this code running correctly in Eclipse all except that it seems no matter where I declare, highest, lowest, average they always seem to stay at "0". I have a feeling the location of the Initialization is not the error since I have tried moving it to inside differ loops.
Stipulations on writing this code are:
Note: You do not need to use array to save each input score for this lab. A Single loop to read in each grade, compare with the current highest grade, lowest grade, and calculate the running sum at the same time.
import java.util.Scanner;
/*Write a program that prompts the user to enter the total number of students first.
*Then ask the user to input each student’s grade and use loop statements to read in each grade.
*Check input grade to make sure 0<=grade<=100, if the user input any other number, print out warning message and ask the user to input a new grade. Display the highest score, the lowest score and the average.
*/
public class LoopStatements {
// Main Method
public static void main(String[] args) {
// Initialize
int grade = 0; // grade value
[Code] ....
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Mar 19, 2014
How to use a constructor with parameters where the user inputs the information? I'm doing a problem where I create a Delivery class that accepts arguments for the year, delivery number within the year, distance code (1 for short distance, 2 for long), and weight of package. The constructor is supposed to also determine the eight digit delivery number (combining the year and delivery number, like 20140054 for this year, package #54).
I know I'm not close to being done but I'm struck on the application with the constructor parameters. If I'm asking the user to input the information, does that mean I have to create a no argument constructor so it will compile? Right now it won't compile because it's asking for the parameters but I can't put them.
This is the class:
public class Delivery {
int year;
int delNum;
double weight;
int code;
[Code] .....
And the error is:
CreateDelivery.java:22: error: constructor Delivery in class Delivery cannot be applied to given types;
Delivery firstDelivery = new Delivery();
^
required: int,int,int,double
found: no arguments
reason: actual and formal argument lists differ in length
1 error
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Sep 26, 2014
I'm writing a temperature converter for class, and I'm done but one piece that I can't wrap my head around.My input scale radiobuttons work fine, but the output scale radiobuttons don't deselect automatically. They're two different button groups and I wrote them identical save for the variable names.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
[code]....
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Apr 13, 2014
I am having trouble grasping 2 dimensional arrays .I have a certain problem:
String[][] words = {
{"Red", "Blue", "Green"},
{"Orange", "Purple". "Yellow"}
[code]....
I ran the code and got OrangePurpleYellowRedBlueGreen.
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Jan 23, 2015
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
[code]....
Total IS those numbers. But question[10] will not cooperate with me and it's getting a bit aggravating as I can't find a logical reason for it to be doing that.how to perhaps lock the value of total and sTotal after 10 button clicks from any?
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Jul 1, 2014
Write a method called isSorted that accepts an array of real numbers as a parameter and returns true if the list is in sorted (nondecreasing) order and false otherwise. For example, if arrays named list1 and list2 store {16.1, 12.3,22.2, 14.4} and {1.5, 4.3, 7.0, 19.5, 25.1, 46.2} respectively, the calls is Sorted(list1) and isSorted(list2)should return false and true respectively. Assume the array has at least one element. A one-element array is considered
to be sorted. public class thirfd {
public static void main(String[] args) {
double[] arr1 = {16.1, 12.3,22.2, 14.4};
double[] arr2 = {1.5, 0.3, 7.0, 19.5, 25.1, 46.2};
isSorted(arr2);
System.out.println(isSorted(arr2));
[code]...
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Feb 13, 2014
I have spent some time thinking about the program, and realize I need two loops-- 1 that keeps track of bricks in a row and 1 that keeps track of the number of rows as the Pyramid rises in height. The Pyramid is supposed to be centered on the bottom of the screen. Three CONSTANTS have been required:
BRICK_WIDTH=30, BRICK_HEIGHT=12, BRICKS_IN_BASE=14.
I tried breaking the scope of things down by trying step-wise refinement. But, I got bogged down. When I tried a method where both loops were included, I got limited success. For some reason, my equation to center along the x axis seems to be doubling the number of bricks. But, the correct number of total rows of bricks was a success. Also, the Pyramid was centered on the bottom of the screen. Another frustrating failure was that the number of bricks would not decrease as the new layers were created. My thought process was instead of using a loop that counts up (i++) I would use a loop that counts down (j--) which I thought would reduce the number of brick in each row as the "y" coordinate was reduced by each count of the BRICK_HEIGHT.
This is the code that "works". Whenever I add the (j--) the results are NOT what I expect.
/*
* File: Pyramid.java
* Name:
* Section Leader:
* ------------------
* This file is the starter file for the Pyramid problem.
* It includes definitions of the constants that match the sample run in the assignment,
* but you should make sure that changing these values causes the generated display to change accordingly.
*
[code].....
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