i want to list files from resources folder like this:
@ManagedBean
public class galley implements Serializable {
private List<String> list;
@PostConstruct
public void init() {
list = new ArrayList<String>();
[Code] ....
but it give me a null pointer exception on fList .... The directory of resources is :
How is this caused and how can I solve it?
I've been closely following a tutorial series, and as far as I can tell my code is exactly the same, but not functioning.
The app throws a nullpointer exception here on "controller.saveToFile(fileChooser.getSelectedFile ());"
// Export data item
exportDataItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (fileChooser.showSaveDialog(MainFrame.this) == JFileChooser.APPROVE_OPTION) {
try {
controller.saveToFile(fileChooser.getSelectedFile());
[Code] ....
There are no errors popping up in the code, and I dont understand why there is a null pointer exception when Im saving this file.
I get a null pointer error on line 17 of the following fragment. I suspect it has to do with the way I am reading the file, but I'm unsure. I can provide more information or code if necessary.
JFileChooser jfc = new JFileChooser();
jfc.setFileSelectionMode( JFileChooser.FILES_AND_DIRECTORIES );
int userInput = jfc.showOpenDialog( null );
if( userInput == JFileChooser.CANCEL_OPTION ){
[Code] .....
It is supposed to create an array of random strings and sort them according to their HTML numbers. It creates the array correctly and even compiles correctly, but has a null pointer exception when it comes to the sorting. (I have cut out other parts of the program that were irrelevant).
the lines that produces the null Pointer Exception is line 24. if(array[i].charAt(0)>array[maxIndex].charAt(0))...and 53.stringSelectionSort(stringArray);
import java.util.Arrays;
import java.util.Random;
/**tests the array.sort() subroutine vs. a
'selection sort' that I will write. a random list
of integers is used first and times are recorded to
determine which one is more efficient. A random list
of strings is also tested.**/
[code]....
what i do keep getting nullpointerexception error whenever i input 1 or 2 whenever the code is asking me to input the type of display to be shown..
this is my error - "Exception in thread "main" java.lang.NullPointerException
at dakilangtaoako.DakilangTaoAko.alphabetSorter(Dakil angTaoAko.java:195)
at dakilangtaoako.DakilangTaoAko.main(DakilangTaoAko. java:91)
Java Result: 1 "
package dakilangtaoako;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;
[code]....
How should null pointer exception be avoided in a program. Should each and every place of access of a variable be checked for null and if null is there own customized exception should be thrown. Is this approach correct for avoiding null pointer exception.
View Replies View RelatedTake a look at this screenshot... my java integrated devlopment envirnment is telling me I have a null pointer on a line with three variables ALL which were initialized.
I thought a null pointer was called when a variable doesn't get initialized.
Edit: Here is the java file and resources being used: [URL]
I am try to move circle.Below is my code...
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
import javax.swing.JPanel;
[Code] .....
And I have error
run:
Exception in thread "main" java.lang.NullPointerException
at swingdesing.Game.buffer(Game.java:32)
at swingdesing.Game.moveBall(Game.java:27)
at swingdesing.Game.main(Game.java:51)
BUILD SUCCESSFUL (total time: 9 seconds)
how to overcome this?
Should the piece of code below set prevent the comboBox from being used? All it does at the minute return a null pointer exception. See I am using the same window but I have an if statement so if a condition is true then it will change certain aspects of the window. I want it to be true if it equals export which is does and it's populated fine but when I try and hide it if the condition equals import it returns a null pointer?
comboBoxEnv.setEnabled(false);
I am getting a NullPointerException at my compareTo statement in this section of my code. Why this is popping up?
public static int findPos(String theArray[], String playerName, int arrayCount)
{
int index;
int pos;
for(index = 0; index < arrayCount; index++) {
while ((index < arrayCount) && (playerName.compareTo(theArray[index]) > 0)) {
index++;
}
}
pos = index;
return pos;
}
Error is also creeping up on the line highlighted in a comment as "THIS LINE", and is linked to the compareTo error above.
while(yesOrNo == 'Y' || yesOrNo == 'y')
{
switch(option)
{
//Add a Player and their Stats to the Array
[Code] ....
I'm new to Java programming (taking a beginner's class) and our assignment is to program a game of Go Fish. I've got all my classes written (Card, CardPile, Player and GoFish). Now the problem is that I'm getting a NullPointerException when I run the GoFish class. The error seems to occur when I ask the program to check whether the player whose current turn it is, has a book (meaning 4 cards of the same value) in their hand. My idea was to run through the values 1 to 13, first checking to see if the value appeared in the player's hand:
if(players[currentTurn].hasCard(hasValue))
And if true, then remove all the cards matching the value from the player's hand, add to a new array of cards and then check to see if this array is of length 4 i.e. a book. If not, return the array of cards to the player's hand.
Here's the error message:
java.lang.NullPointerException
at CardPile.searchValue(CardPile.java:88)
at Player.hasCard(Player.java:15)
at GoFish.main(GoFish.java:98)
It references the following lines of code:
In GoFish.main:
// At the end of each turn, check to see if player currentTurn has made a book.
boolean hasBook = false;
int hasValue;
for (hasValue = 1; hasValue <= 13; hasValue++) {
// Runs through player's hand and removes all cards of the same value between 1 and 13 and places in a new array.
[Code] ....
I cannot figure out why I am getting the null pointer exception error!!!
i have a j sf application that is using web-services to communicate to another application and pass some parameters to it.The application has three methods one to call the webservice,another to insert some values into a database and the third method to call the two methods when i click a button in a form.The methods a are
update() this is for calling a webservice and passing parameters to it.
insertt() to in sert to a database.
all() to call the above two.
when i call upadate and insertt in all method am getting an error java lang null pointer exception but when i call just one of the methods it executes successfully.This is my code package softmint.com;
import java.sql.Connection;
//import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
//import java.text.SimpleDateFormat;
import javax.xml.ws.WebServiceRef;
[code]....
My web application will load an applet with SWING components (Menu bar) on successful login to application.
Once page is loaded, i choose a menu item from the menu bar and click on it. Dynamic menu bar is loaded for the selected menu item. After that i am not able to perform any action on menu bar. Ending up with below error.
Note: My Application is absolutely working fine till JRE 1.7.17. But when i upgarde to higher version of JRE like 1.7.25 and above i am getting below error.
Exception in thread "AWT-EventQueue-4" java.lang.NullPointerException
at javax.swing.RepaintManager.scheduleProcessingRunna ble(Unknown Source)
at javax.swing.RepaintManager.addDirtyRegion0(Unknown Source)
at javax.swing.RepaintManager.addDirtyRegion(Unknown Source)
at javax.swing.JComponent.repaint(Unknown Source)
at java.awt.Component.repaint(Unknown Source)
[Code] ....
I have an input text file as file.txt where, it consists of only real values separated with commas, and arranged as rows as columns as mentioned below :
1,2,3,4,5,6,10,5,8,9
1,4,7,8,9,0,6,4,3,2,1
2,4,5,8.1.3.4.6.7.9.0
the number of rows is 100 and the number of columns are 9, that is they are fixed.Above is just an example, the file consists of decimal values.What I require is for each column of values I need to find out it's average or mean, that is in above example,
for 1st column:(1+1+2)/3
for 2nd column(2+4+4)/3
for 3rd column(3+7+5)/3,,,,,,,like this till the last column.
So I need to take the input from the .txt file, calculate the column average of each column and the average of each column must be displayed as output. I have done a bit of coding, but it is giving a run-time error as NullPointerException.I will forward my code as attachment, the reading of file, is done as string in java and then it must be converted to double values, also to read the comma separated input from a file I have used the split().
I'm getting constructor null pointer exception but i don't know what has gone wrong...
private int capacity; // maximum capacity of the board
private double minimum; // minimum distance of the flyer
private SortedLinkedList sortedList;
private int size = 0;
public ScoreBoard() {
capacity = 10;
minimum = 0.0;
sortedList = new SortedLinkedList();
[Code] ....
I am trying to export data from a jtable to a pdf report but every time i try running the code it gives me this exception:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at GUI.QC_receiving_book.printButtonActionPerformed(QC_receiving_book.java:309)
at GUI.QC_receiving_book.access$600(QC_receiving_book.java:26)
at GUI.QC_receiving_book$7.actionPerformed(QC_receiving_book.java:165)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
[Code] ....
I tried avoiding the null exception by using the if statement but it didn't work. The row I choose from the table is full meaning there are no empty attributes. and all the data are imported from a mysql database to the table as String so there can't be any casting errors.
This is the part of the source code with the problem and i will also post the printing method. I tried debugging the class and when stepping into the first if statement it opened the jTable.java file and pointed at the getSelectedRow() method and this sentence "variable information not available.source compiled without -g option"
private void printButtonActionPerformed(java.awt.event.ActionEvent evt) {
if(samplesTable.getSelectedRow() >= 0){
int row = samplesTable.getSelectedRow();
System.out.println(row);
for(int x=0;x<samplesTable.getColumnCount();x++){
String value = samplesTable.getModel().getValueAt(row, x).toString();
[Code] ....
Question 1: I am working on an assignment where I have to remove an item from a String array (see code below). When I try to remove an item after entering it I get the following error "java.lang.NullPointerException." I am not sure how to correct this error.
Question 2: In addition, I am having trouble figuring out how to count the number of occurrences of each string in the array and print the counts. I've been looking at other posts but they are more advanced and I have not yet learned how to use some of the tools they are referring to.
private void removeFlower(String flowerPack[]) {
// TODO: Remove a flower that is specified by the user
Scanner input=new Scanner(System.in);
System.out.println();
System.out.println("Please enter the name of the flower you would like to remove:
[Code] ....
This method keeps throwing a NullPointerException. Not only that, but its not doing what I want it to do.
Heres the code:
/*
Remove all the numbers from the queue and push onto the stack until an operator is reached
*/
private static void processQueue() {
// Check what is at the front of the queue. If an operator is found or the queue is empty, exit method.
while(queue.front() != null || !queue.front().equals("*") || !queue.front().equals("/") || !queue.front().equals("%")
|| !queue.front().equals("+") || !queue.front().equals("-"))
{
stack.push(queue.removeFront()); // push the operand onto the stack
}
}
Here is the method that calls the processQueue() method
/*
Process the mathematical expression using a stack and a queue
*/
private static double processExpression() {
// insert all elements from the stack to the queue for processing
while(stack.top() != null) {
queue.insertBack(stack.pop());
[Code] .....
I'm using a PrimeFaces UploadedFile xhtml page to select a csv file to read and write using a managed bean (SuperCSVParser.java). The file is read and written to an entity class which then persists the data to a database. The application works fine if I specify a file path on the physical server and select a csv file on that file path. But for the production version I want the user to select ANY file name from ANY directory on their local system.
I know about the FacesContext methods and I've looked at some methods from the java.io File class. Most of these methods are about getting the path from the server, where I want to 'pass' the path String from the client machine to allow the uploaded file to go through. When I try with the below code I get:
java.io.FileNotFoundException: data.csv (The system cannot find the file specified)
I'd like to know what I'm doing as I prefer not to explicitly declare a path in the final app. I'm almost sure that's possible.
<h:form enctype="multipart/form-data">
<p:fileUpload value="#{SuperCsvParser.file}"
mode="simple"
auto="true"
[Code].....
I'm getting an error on line 137 and all it is rsmd = rs.getMetaData();The error happens only after I press a JButton and it is
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExceptionat softwareDesign.createAccount.actionPerformed(createAccount.java:137)
There is a lot more to it but that has nothing to do with my code it's just the stuff with Eclipse anyway I want to know how do I fix this problem?
I have a JSF bean which is request scope and corresponding JSF UI page. when user tries to open this page, we are getting exception 'Cannot instantiate user.java class <default constructor>'. This does not come always. It comes very rarely. JSF version is 1.2
View Replies View RelatedAbout creating views,
1. When we have a view and this uses two or three managed beans and not only one, is this ok? is a good design?
2 If we have two views and both of them only share one functionality (they need to display datatable with clients) , for the second view and for the shared functionality, should I in the managed bean for the second view create the same method that gets the clients or reuse the method in the managed bean created for the first view?
I have a situation to load data while JSF page loads. Also have a filter which populates user information from http request.
I was expecting the filter first to populate the user information and in the managed bean get method to verify the user information and get the data (from database). But in this case i see the managed bean get method is invoked before filter populates user information and i get null pointer exception because the user information is null.
I had to work around to get the user information from FacesContext in the managed bean get method because the user information wasn't available. Is there a way to make sure the filter is invoked first?
I am trying to restrict the number of views in JSF 2.0.2 using
<context-param>
<param-name>org.apache.myfaces.NUMBER_OF_VIEWS_IN_SESSION</param-name>
<param-value>5</param-value>
</context-param>
In my case my managed bean is View Scoped and it supports a UI page which has multiple forms and each form is submitted as AJAX POST request.
As per the statndard, setting restriction to 5 should create 5 views and after that based on LRU algorithm the oldest views should get deleted if 6th views is created.
Therefore any action on the oldest view will throw the ViewExpiredException and i simply redirect the user to view expired page.
1) When i set the restriction to 5 views, i open 4 tabs with 3 forms each.
2) I submit the 3 forms on first tab everything works fine.
3) As soon as I go to 2nd tab and submit the first form thr, i get view expired exception
4) It seems I am exceeding the number of views I mentioned in web.xml
I want to know :
1) Does every AJAX POST submit itself creates a view ?
2) How I can count the number of views created in a session ?
3)Can i force expiry of a view in JSF 2.0.2 while the session is still alive ?
4) Normally JSF 2.0.2 session cachces the views. Lets assume session is alive the entire day but a view was created in morning at 9:00 AM and is not used again the entire day. Assuming that session doesn't reaches the max number of views it can save in entire day, will the view created in morning expire on its own after certain interval of time ? If not , can we still force its expiry while keeping the session alive ?
I have a requirement where in my primefaces datatable ,the filterMatchMode attribute(like any part of field,whole field) needs to be selected by the user by select menu .
To achieve this i have declared a variable in my viewscoped managed bean as filterCriteria and set the filterMatchMode attribute as filterMatchMode="#{beanName.filterCriteria}".The bean variable is getting set in the managed bean on submit but the filtering is not happening,i am getting empty message.
Also when i remove the keyed in value from filter box the data table is not restored which otherwise must be restored in normal situations. I have used and modified the example code given in primefaces showcase here.The code snippet is as below
<h:form id="tblFrm">
<h:selectOneMenu id="filterOptions"
value="#{dtFilterView.filterOption}" required="true"
requiredMessage="You must select an option!">
<f:selectItem id="hd1" itemLabel="Select" itemValue="#{null}" />
[code]....
I read JEE6 doc and confused with : Does container managed entity manager (injected by PersistenceContext annotation) is thread-safe in stateless session bean in multiple-thread env?
See code below, if there are 2 requests to stateless sesion bean in 2 concurrent threads , is it using same Entity Manager Instance or not?
@Stateless(name = "HRFacade", mappedName = "HR_FACES_EJB_JPA-HRFacade-HRFacade")
public class HRFacadeBean implements HRFacade, HRFacadeLocal {
@Resource
SessionContext sessionContext;
@PersistenceContext(unitName = "HRFacade")
private EntityManager em;
[Code] .....