i created a class and a constructor for the class. then i used getters and setters.in the setters i'm trying to write a line that will be -
if (num < 0|| num>120) {
dont change value and do nothing
}
else{
num1 = num
}
how can i do this ? i tried to put an empty curly braces but it gives me an error.
@Override
@SuppressWarnings("unchecked")
public TableCell<S, T> call(TableColumn<S, T> p) {
TableCell<S, T> cell = new TableCell<S, T>() {
@Override
public void updateItem(Object item, boolean empty) {
if (item == getItem()) {
return;
}
The line in the code above TableCell<S, T> cell = new TableCell<S, T>() {
I don't understand how curly braces follow an assignment statement?What does the line of code mean?
I have read some on this but I'm trying to understand a code and the following part confuses me
if( thisCount == bestCount )
bestCandidates.add( candidate );
else if( thisCount > bestCount ) {
bestCount = thisCount;
bestCandidates.clear();
bestCandidates.add( candidate );
}
}
What I find confusing is this: If I am not mistaken the need for curly braces occurs when using more than one statement and if you use else statements.
So I wonder if I have missunderstood about the else statement and that you dont need curly braces around a one statement if statement that is followed by an else statement...
At this moment in time my program compiles and runs as I want it to, but when I look at my code I see that my While Loops braces are placed inside my Try Block. When I move these braces outside of the Try Block, next to the WhileLoop, the program doesn't run like I want it to.
Likewise, when I place the While(answerIsCorrect) inside the Try Block, it doesn't work like I want it to either.
Also, my problem is on Lines 17 and 18.
import javax.swing.*;
import java.util.Random;
public class SwingInputExample
{
public static void main(String args[])
{
int firstNumber=0;
int secondNumber=0;
int correctAnswer=0;
String studentGuess = null;
[Code] ....
I saw code like this.
Set<String> set = new HashSet<String>(){{ add("Hello"); }};
I can understand that it is a HashSet with one element "Hello" in it. I don't understand this syntax. Why there are double curly braces?
I'm doing some revision for my OCAJ atm, & I came across this code in a mock question which takes two int arguments & simply returns the larger.
public int max(int x, int y){
if (x > y)
return x;
return y;
}
When evaluating it I thought this would be invalid code as would always return x. But it transpires I was way off & that this actually works! In playing around with it, it seems like the first return statement is treated as:
if {// this bit } & the second return is treated as: else{ //this bit}.
What baffles me though is that you can put any amount of additional statements before the second return and it continues to work, however if you put even a single statement before the first return, the whole thing falls over.
I guess my two questions are - Am I right in my discovery above ( that statements preceeding the first return will always break it)? & secondly is this a good way of coding? for readability, I would always do it as:
public int max(int x, int y){
if (x > y){
return x;
}
else{
return y;
}
}
Here if we give input from a text file from a disk and (a[b+c{d}]-v) is true and{a-(b]} is false but i get some syntax errors ...
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Stack;
public class Syste {
private static String expr;
[code]....
I need a pattern that matches Hello Smith (STL Terminal) (15.0).
View Replies View RelatedSo from what iv learnt in Java and programming in general is that using a case statement is far more efficient that using multiple IF statements. I have an multiple IF statements contained within a method of my program, and would like to instead use a case statement.
public String checkPasswordStrength(String passw) {
int strengthCount=0;
String strengthWord = "";
String[] partialRegexChecks = { ".*[a-z]+.*", // lower
".*[A-Z]+.*", // upper
".*[d]+.*", // digits
".*[@#$%!]+.*" // symbols
[code].....
So I want to make a simple Java that ask the user to pick a powers and it has two options.If the user picks magic then execute the first if statement then ask the user again which type of magic the user wants.I can't make it work it keeps printing the else statement. Why is that?
import java.util.Scanner;
public class Variable {
static Scanner zcan = new Scanner(System.in);
public static void main(String[] args)
[code]....
I have a HashMap with multiple values at runtime. In that map one key has empty value , how to avoid this value to add in a list. some code sample is below:
public HashMap getLoop2Map(Map map, String xslFile , int sheetNo){
HashMap hashMap = new HashMap();
try{
ArrayList list = new ArrayList();
System.out.println("-------Map : " +map);
list.add(map.values());
//System.out.println("------- boolean : " +val);
System.out.println("------List : " +list);
}
I do not want to add the empty value in a list ...
result in map
-------Map : {Free Text Entry={},
Mouth / Throat={Free Text Entry={Free Text Entry=<FORMFILENAME>EditChartPhysicalExamText.form
</FORMFILENAME><TAG>"<MUSCULOSKELETAL.PE>"</TAG>},
Salivary Glands Condition={Salivary Glands Condition=MouthAttribute},
Examination Overview- Mouth / Throat={Examination Overview- Mouth / Throat=MouthAttribute},
Tonsils={Tonsils=MouthAttribute},
[Code] ....
I want to downoald a file stored in system directory but when downloading the file in jsf page I get it empty. this is my xhtml page :
<h:form>
<h:commandButton value="Download" action="#{helloBean.downloadFile}" />
</h:form>
and my managed bean :
@ManagedBean
@SessionScoped
public class HelloBean {
public void downloadFile() {
File file = new File("C:datacontacts.doc");
HttpServletResponse response = (HttpServletResponse)
[Code] ....
I have an output file which should contain some total values from calculations, but at the end it is empty.Here is my code in the try catch block:
BufferedWriter bwArea = new BufferedWriter(new FileWriter("." + ToolKit.fileSeparator() + OUTPUT_FILE_AREA));
bwArea.close();
in the method after that I have:
PrintWriter outArea = new PrintWriter(new BufferedWriter(
new FileWriter("." + ToolKit.fileSeparator() + OUTPUT_FILE_AREA, true)));
Integer total=traffic[0]+traffic[1]+traffic[2]+traffic[3];
double greenPercent = ((double)(traffic[0] )) / total*100;
double yellowPercent = ((double)(traffic[1]))/total*100;
double redPercent = ((double)traffic[2])/total*100;
double blackPercent = ((double)traffic[3])/total*100;
[code]...
I have 2 classes:
1) productType that have name and price of the productType and an empty consturcor.
2) superMarket that have name of supermarket and arraylist of productTypes (
private ArrayList<ProductType> products;
) and an empty constructor.
In each class I have function that get input from console and should store it into each class variables.
In productType i have function:
public void getFromUser() throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter product name:");
name = br.readLine();
System.out.println("Enter price:");
price = Integer.parseInt(br.readLine());
[Code] ....
The main is something like:
public static void main(String[] args) throws IOException{
SuperMarket s1 = new SuperMarket();
SuperMarket s2 = new SuperMarket();
s1.getFromUser();
}
The problem is when i get to line "products.add(i,p)" I get java.lang.NullPointerException
In the debug mode I can see that when I get to this line the "products" is null.
why do you think this happening, when I do "new SuperMarker()" in the main it should run the empty constructor and create new arraylist...
I've been beavering away with Java for a few months. But as with all languages the String implementation looks designed to trip up even experienced programmers.
My current development gets data from various sources outside my control. When I get a string I want to test if it is empty/null/or whatever. Simple enough one thinks.
But if you search the internet you see everone seems to have a slightly different approach. So what is the best way of determining that a string is not useful to you?
I've had success with this
if(string == null || string.length() == 0)
But I've seen people using methods - not necessarily of String (e.g equals, empty) and regular expressions.
What is the best approach to this considering coding efficiency and/or processing efficiency (accepting you'd have to be processing a lot of strings for the latter to be an issue).
im trying to make a gui im trying to add a new jbutton for every empty cell in the array, and for some reason its giving me array index out of bounds error, this is what i have, im trying to to do it in an 80 by 80 array.
public JButton[][] buttons = new JButton[80][80];
public void addButtons(){
for(int i=0;i<buttons.length;i++){
for(int j=0;i<buttons[i].length;j++){
buttons[i][j]= new JButton();
}
}
}
I'm writing basically my first program for school. I've written small ones, following instructions, but this is the most vague. I'm having issues. I can't figure out what the error means. I'm not done with the code, but I think the ArrayList is throwing me off. I'm trying to gather user input and sum the total. Here's the code:
package graduationplanner;
import java.util.ArrayList;
import java.util.Scanner;
import java.lang.Double;
public class GraduationPlanner {
public static void main(String[] args) {
[Code] ....
I am learning Java on my own, and I am creating little programs to do so.The program below asks the user to input text and hit enter. When user does that, it asks if that is correct. If the user enters "y," the program ends. That's good.If the users enters "n," the strGrategul is set to empty which triggers the while statement to start over again. That's good. However, when the program asks the user to "Tell me one thing you are grateful for..." it doesn't wait for user input. Instead it skips to "You said ''? Enter 'y' or 'n'" It thinks the user enter an empty line.
public static void main(String[] args) {
String strGrateful = "";
String strGoal = "";
String strContinue = "";
Scanner scn = new Scanner(System.in);
[code]....
How can I get enter(return) as empty input from user?!
scanner.next will wait until I input a string ...
But I want it when I hit return sets the variable to empty string ...
I am having issues with the program below everything works but I can't figure out a way to add code that if a user just hits enter without inputting anything it says "entering in nothing is not a valid choice" I am stuck on how to compare a int to a string ...
//import statements
import java.util.*; //for scanner class
// class beginning
public class Guess {
public static void main(String[] args ) {
//Declare variables area
[Code] ....
I am trying to create an array filled with the object Card. It keep throwing the exception that the "deck is empty". I am not sure why that's happening because the code for filling the array seems fine.
public class Deck {
private Card[] deck;
private CardPile cardPile;
private int numCards;
public Deck() throws InvalidDataException{
this.deck = new Card[52];
[Code] .....
I am trying to create an empty array that has no assigned length as the amount of elements it needs to hold will be dependent on another value. I then want to use a while loop to assign values to it. Here is an example of what im looking for it doesnt work. Iam trying to do:
int x = 12;
int i = 1;
int k = 0;
int[] factors = {}
while (i<x) {
if (x%i==0) {
factors[k] = i;
k++;
i++;
This is what i've done so far.
table.addKeyListener(new KeyListener() {
public void keyPressed(KeyEvent e) {
if (e.getKeyCode()==KeyEvent.VK_ENTER) {
model.addRow(new Object[]{"", "","",""}); } }
public void keyReleased(KeyEvent e) { }
public void keyTyped(KeyEvent e) { } } );
I've added JTable to JPanel and used DefaultTableModel. I have to add a new empty Row to table after i press enter key. But somehow I've not been successful so far.
I am developing an dashboard application in Java, JSTL, MySql, Apache Tomcat 6.I have the below files
1. Dashboard.java (model)
2. DashboardDAO.java (dao)
3. DashboardController.java (Controller)
//Source
protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
String forward = "";
forward = LIST_DASHBOARD;
HttpSession session = req.getSession(true);
[code]....
It works in the first time. But, after sometime the data is not retrieved and display empty screen. Once, i stop and start the server again, the data is getting retrieved again. But, later when we refresh the empty page is getting displayed again.
I've been trying to get my program to not accept empty strings when the user inputs, but I'm having some difficulties. I've tried for loops, as well as while loops.
import java.util.Scanner;
public class GasMileage
{
/**
* displayIntro
* This method displays the introduction to the user
*/
public static void displayIntro()
[Code] .....
I have a problem with my JTable.
When i run my program i see a JTable with data in it. The first 3 columns are filled with data, the next one is empty. Other columns that come afther the empty one are also filled.
So my 4th column is empty. But it only apears empty, cause when i move the 4th column to the left. The same column that was at 4th place is now at 3th place and filled up with data.
So the 4th column apears empty but it contains data when i move it to the left or the right.
Why does it show an empty column at the 4th place?
Some printscreens to get it clear:
In attachment:
attachment1 = 4th Column is empty
attachement2 = 4th column is moved to 3th place and is filled with data.