I have a JFrame jf and JPanel jp on it. jp has five TextFields named cel1, cel2.. cel5. I wish to construct a String Cel + for loop index and run a for loop to reset the values of all the text fields using a single statement such as cel1.SetText("abc"). Similar things can be done in foxfro. How does one do it in java?
View RepliesGiven the case I have an object which is assigned only once. What is the difference in doing:
public class MyClass {
private MyObj obj = new MyObj("Hello world");
private MyClass(){}
//...
}
and
public class MyClass {
private MyObj obj;
private MyClass(){
obj = new MyObj("Hello world");
}
//...
}
Is there a difference in performance or usability? (Given also the case there are no static calls expected) ....
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () {
int [] myInt; // A local, member variable (because "static" keyword is not there) declared
} mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
Given a reference variable : Car c1 = new Car();
when we create another variable and set it equal to the first : Car c2 = c1;
we're pointing c2 at the same car object that c1 points to (as opposed to pointing c2 at c1, which in turn points at the car). So if we have code like,
Car c1 = new Car();
Car[] cA = {c1, c1, c1, c1};
are we doing the same? Are we creating four *new* reference variables, each of which points at the same car (again as opposed to pointing them at c1 itself)? I think so, but want to make sure I'm understanding this correctly.
I am trying to concatenate 4 strings together to later be able to make them all upper case, or lower case or get the length. I keep getting an error on line 16.
import java.util.Scanner;
public class userInput
{
public static void main(String[] arg)
{
Scanner keyboard;
keyboard = new Scanner(System.in);
String msg1, msg2, msg3, msg4;
[Code] ....
I'm trying to do something like this:
Java Code:
for (int i=1; i<2; i++);
int randomNum = rn.nextInt(range) + 1;
if (randomNum == CardList.CARD_NAME[randomNum]){
} mh_sh_highlight_all('java');
But the CARD_NAME variable is a string. I just want to compare the array to the integer.
public static void main(String[] args) {
String str1="Java";
str1="one";
System.out.println("str1="+str1);
}
String object is stored in a private final char array in String.java.
private final char value[];
The basic characteristic of a final variable is that it can initialize a value only once. By marking the variable value as final, the class String makes sure that it can’t be reassigned a value.
so the String objects can be initialized only once but the above code shows that str1 was initialized first with "Java", then it can be re-assigned value "one" bcos the output is one. If it can be re-initialized, basic characteristic of final variable is not satisified and hence how can we call String objects are immutable?
At first I wanted to just use an array and set each day a value, however I was told that it has to be stored as a string.
Design and implement the class Day that implements the day of the week in a program. The class Day should store the day, such as Sun for Sunday. The program should be able to perform the following operations on an object of type Day:
A. Set the day.
B. Print the day.
C. Return the day.
D. Return the next day.
E. Return the previous day.
F. Calculate and return the day by adding certain days to the current day. For example, if the current day is Monday and we add four days, the day to be returned is Friday. Similarly, if today is Tuesday and we add 13 days, the day to be returned is Monday.
G. Add the appropriate constructors.
H. Write the definitions of the methods to implement the operations for the class Day, as defined in A through G.
I. Write a program to test various operations on the class Day.
import java.util.*;
public class Day {
static Scanner readinput = new Scanner(System.in);
String day;
public Day(String day) {
[Code] ....
So right now if I run my code it allows me to type in a day, then it gives me the next and previous day, the last part is to add X days to it. Ideally I would like to be able to take the day entered, depending on the day set a numeric value, then add prompt for number of days you want to add. The program should then use modal (%7 ) to add value to the value that was given based on the day, and then translate it back into a String value (the day).
I need to allow users only enter integer into a String variable, "input" and I am not sure what statement to use.
import java.util.Scanner;
public class assq2b {
public static void main(String []args) {
Scanner reader = new Scanner(System.in);
String input,b;
[Code] ......
I have created an enumerated data type that represents months. In my program I have asked the user for the month. I hold the month entered by user into a string variable. From that string variable I'm trying to display the month using my enumerated data type. I know I can use if statements, but is there another simple way to do it?
import java.util.Scanner;
public class demo {
//Enum class called month that has constants in it representing months
enum month{january,february,march,april,may,june, july,august,september,
october,november, december};
[Code] ....
I am trying to make a program that calculates the change due in dollars and cents. The user inputs both the amount due and the amount tendered. My program only works with whole numbers?
View Replies View RelatedI am trying to write a program and the name variable can only store letters,dotes and spaces. But whenever I enter a space, the program doesn't work. Following is my code.
import java.util.Scanner;
import java.util.*;
public class Space {
public static void main(String []args) {
Scanner reader = new Scanner(System.in);
[Code] ....
I have searched for totalPay is always 0 and the responses are not related to my problem (that I can tell).This is a class assignment and I have other questions besides why the method is not working.
Here are the instructions: Create class Employee which contains a String variable Employee Number, a String variable Employee Name, an integer Hours Worked, and a double Pay Rate. Create get and set methods for each variable. Provide method "totalPay" which calculates and returns the total pay by multiplying the hours worked by pay rate. Use figure 8.12 as an example of an object with get and set methods.
Unlike other examples of this type question online this one has Employee Number as a String variable. The book is How to Program Early Objects by Deitel 9th edition.We have instructions to do only what she has told us too. At this point it is objects and getter and setter methods. It is only the beginning of week 2.
ON THE LINES WHERE I HAVE QUESTIONS I AM COMMENTING IN ALL CAPS. NOT SHOUTING, JUST TRYING TO MAKE IT EASIER
package test11;
import java.util.Scanner;
public class Test11 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
[code]..
Essentially I cannot figure out how to get the method getTotalPay to be called by the Scanner and do the math. I also have this random bracket problem that showed up about an hour ago.
The concept I don't get is that if I omit this.employeeNumber =id; etc. I error all over the place. If I change it to this.employeeeNumber = employee Number Netbeans tells me it is assigning itself to itself, which I know. When I try to use id instead of employeeNumber I get errors all over. If i remove "this" from it the same happens. why in public class employee I have to change to those values (id, name, etc) in the construct and set them again? I don't see where or how they can be used, so why do i have to do it?
How do I use a variable in an if statement to return a public void method from another class? I've tried:
System.out.print("select 1 - 6: ");
Scanner myScanner = new Scanner(System.in);
myScanner.nextInt();
if (myScanner.nextInt()==1) {
carSelection colour = new carSelection();
colour.carSelection();
The method colour in class car selection is just 4 print line statements? I've // out the if statement to see if it is correctly calling the method and displaying the data and it is?
What is variable shadowing?When does it occur?
View Replies View RelatedRegarding the code examples in Head First Java, this is from Chapter 5, regarding the beginning creation of the dot com game. There are two classes in quesiton
the first is the SimpleDotComTester class:
public class SimpleDotComTester {
public static void main(String[] args)
{
SimpleDotCom dot = new SimpleDotCom();
int[] locations = {2, 3, 4};
dot.setLocationCells(locations);
String userGuess = "2";
String result = dot.checkYourself(userGuess);
}
}
and the second one is the code for the checkYourself () method in the SimpleDotCom class
public class SimpleDotCom {
int[] locationCells;
int numOfHits = 0;
public void setLocationCells(int[] locs)
[code]....
Now I noticed that both classes use a variable called result; the program runs fine, but assume from the example that you can use the same variable name two different classes;
i have a datatable with id= tblId#{emp.id}
<c:set var="tableID" value="tblId#{emp.id}">
displaying employee details inside c:forEach
closing dataTable.
[code]...
For ex.Displaying 5 table dynamically.Need to validate check box selected or not.5 table are displayed.But it shows 5th table row id only.It is because of local varible declaration?
I'm making a program where the user enters an ID number and can submit the amount of sales that person made for a specific product and write to a file. One of the things I have to do is making a running sum of the sales for each product for all people combined as well as an accumulation of the a persons sales every time he enters data. Everything seems to be working execpt my values like person1Total, person2Total...etx and product2Total.
When I try to write them to the file, they always come out at 0.0 even though they should be the sum of the indexes of the array sales.
import java.io.*;
import java.util.Scanner;
public class SalesReport {
// private static double p1Total, p2Total, p3Total, p4Total;
private static double product1Total, product2Total, product3Total, product4Total, product5Total;
private static double person1Total, person2Total, person3Total, person4Total;
public static void main(String[] args) throws IOException
[code]....
I'm working on a program where the user inputs song information (name, artist, filesize, duration) which is stored in a database. Once the user adds a song, the details should be stored in the first empty song slot (4 song slots total) and then taken back to the menu interface.
What I'm having trouble with is that I can add the first song fine (song1), but when I try to add another song, the information entered into song1 is gone. I've worked out that this is because every time I call upon the addNewSong() method, I'm creating four Song objects that are brand new with the line:
Song song1 = new Song();
Song song2 = new Song();
Song song3 = new Song();
Song song4 = new Song();
How to fix this problem is where I'm stuck because if I move these lines elsewhere, I get a 'cannot find symbol - variable song1' error.
Here is my code:
public class SongDatabase {
Scanner console = new Scanner(System.in);
public void addNewSong() {
Song song1 = new Song();
Song song2 = new Song();
Song song3 = new Song();
Song song4 = new Song();
if (song1.isEmpty()) {
[code]....
I trying to display the value of a variable from a method, but I don't know why it will I can't do it.
//Java extension package
import javax.swing.JOptionPane;
public class Palindrome
{
public static void main(String[] args) {
int number = 0;
int palindrome = 0;
[Code] ....
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;
[Code] .....
How can I make variable from table value? Example:
Java Code:
String table [] = {"vara","varb"};
for(int i = 0; i < table.length; i++)
{
int table[i] = i;
} mh_sh_highlight_all('java');
And vara = 0, varb = 1 here.
Is this even possible?
i'm new withh java netbeans, and i want to make program where variable from database. how to get value from database to use in variable/
View Replies View RelatedI have a problem with my code. When, on strausParser class, i create the new object Beam i give him an array of Node object called "nodiestremi".
The problem is that when a Beam is created, the Beam created before take the Node of new Beam. Why it appends?
public class Main {
public static void main(String[] args) throws NumberFormatException, IOException{
SetFile.setupWindows();
Structure structure = new Structure();
}
public class SetFile {
}
I get an output like this:
Import node complete
0 0 0 1
0 1 1 2
0 1 1 0
0 2 2 4
Import beam complete
and not like this:
Import node complete
0 0 0 1
0 0 1 2
0 0 1 0
0 0 2 4
Import beam complete
My code has a method where the users input a bunch of variables and then those variables get added together in a new variable. What I want to know is how do I call the variable that is in the other method to another method?
import java.util.*;
public class Calc{
public static void main (String [] args){
determinevalue1();
determinevalue2();
determineTotalvalue(double value1, double value2);
[Code] ....
I have a class Tree in which all the methods to build a tree are in place. But however I would want variable of by Tree which is pointing to the last node being added to the tree.
So basically every time you keep adding a node to the tree you tail pointer gets updated to point to the last node. I have this so far.
public class NonEmptyTree implements Tree {
private Tree left;
private int data;
private int leftleafCount;
private int rightleafCount;
private Tree right;
private Tree tail; // This variable must be shared by all the object. There needs to just one tail pointer to the tree.
public Tree insert( data ) {
tail = // gets updated every time when new node gets added.