Null Is Easily Printed As Value Of Variable Without Exception Being Thrown
May 27, 2014Sometimes a nullpointerexception is thrown, in some cases null is easily printed as a value of a variable without an exception being thrown.
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JSP :: Navigating When Exception Is Thrown
Oct 10, 2014 need to navigate/render a jsp when a custom exception is thrown from a code block in my app.for that in web.xml I have configured the error handling
<error-page>
<exception-type>com.exampl.RecordNotFoundException</exception-type>
<location>/WEB-INF/errorpages/recordnotfound.jsp</location>
</error-page>
Code block
@RequestMapping(value = "/record", method = RequestMethod.GET)
public ModelAndView getPages() throws RecordNotFoundException{
throw new RecordNotFoundException("E888", "This is custom message X");
}
My questions are:
Is this the correct way to invoke a jsp when my code throws an exception?Do I need a try catch block to handle the thrown RecordNot Found Exception, if yes how would I navigate to the jsp from the catch block?
Socket Closed Exception Being Thrown
Feb 10, 2014I have been working with socket programming. I was trying to develop a two way communication from server to client. The data is being received when sent from server to client but there is a problem when I am sending from client to server.
I am getting an error as "Socket is closed" pointing to the line where I have created a BufferedReader. I have simplified some part of my code to be very specific.
Code attached.
import java.io.*;
import java.net.*;
import java.util.*;
public class Server
{
public static void main(String args[])
{
String id="policeone";
int hashcodeid=0;
[Code] ....
Error::
Receiving string from client: 'java.net.SocketException: Socket is closed
at java.net.Socket.getInputStream(Socket.java:872)
at Server.main(Server.java:51)
Why Is Exception Not Thrown When Connection Is Terminated
Jul 27, 2014Below is a code of a simple file downloader in java. I want to detect an exception when the connection is broken in the middle of downloading a file. Now, I run the code and in the middle of downloading the file, i turn off my wifi with keyboard wifi off button. Doing this the program hangs forever without throwing any exceptions and without terminating. It seems it blocks forever.why is exception not thrown? Secondly, in the following code you can see this line //con.setReadTimeout(2000); which is currently commented out. Removing the comment and running the program, now if connection breaks in the middle by turning off wifi then it waits for 2 seconds and then if it cannot read then it terminates without throwing exception. So, again in this case why is it just terminating and not throwing any exception?
Java Code:
import java.io.FileOutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.util.*;
[code]...
Unreported Exception - Must Be Caught Or Declared To Be Thrown
Oct 4, 2014I am getting the above error and am not sure which direction to proceed. In the class, the only way we have discussed getting user input is by System.in.read. I have searched and apparently found better methods for getting user input, but wanted to stick with what has been presented thus far.
Assignment Directions:
1. Create a new class named “valuemethod”
2. Create a new method named “Main”
3. In Main Write the code that will call the method EnterPay and YearlySal
4. Create a new method named “EnterPay”
5. In the EnterPay method Write the code that asks the user to input their hourly wage. Use the formula to calculate their yearly salary: wage * 2040. Return the yearly salary to the main method
6. In the main method write the code that will display this: “Your yearly salary is:
Java Code:
package valuemethod;
public class Valuemethod
{
public static void main(String[] args)
//throws java.io.IOException -- moved to EnterPay
[Code] .....
Servlets :: Filter Behavior When Exception Is Thrown
Apr 21, 2014I just wanna confirm that when a certain processing throws an exception even when said exception happens inside doFilter, any servlet container will never proceed to the next filter right?
View Replies View RelatedIllegal State Exception Thrown From RequestFocus In JavaFX
May 2, 2015I am attempting to create a very simple game where two squares move around and each can see the other square moving. This is a multi-player game over a TCP network using JavaFX. I am getting an illegal state exception when I call requestFocus(). This is my server:
public class GameServer extends Application {
ObjectOutputStream p1out;
ObjectOutputStream p2out;
int PLAYER1 = 1;
int PLAYER2 = 2;
[Code] .....
True / False Result Cannot Be Printed Due To Variable Answer
Jun 30, 2014Code in the book is written exactly like this:
import java.util.Scanner;
public class AdditionQuiz {
public static void main (String[] args){
//Generate random two integers using utility System.currentTimeMillis
int n1 = (int)(System.currentTimeMillis() % 10);
int n2 = (int)(System.currentTimeMillis() / 7 % 10);
[Code] ....
however the true/false result can not be printed due to the "answer" variable...
Exception Thrown If User Enters Negative Number - Program Gets Suspended
Oct 19, 2014In my cs class, we have to write a program that throws an exception if the user enters a negative number, the program should prompt the user to enter only positive numbers and then let them retype the number. But everytime I throw an exception, my program gets suspended.
What am I doing wrong, or is there no way to continue a program if an exception is thrown? Does the program automatically get suspended when an exception is thrown?
try{
do
{
N = kb.nextDouble();
if(N<0) {
throw new NegativeArraySizeException();
}
else
j++;
}
while(j==0);
fill.size(N);
}
catch(NegativeArraySizeException e) {
System.out.println("The number you entered must be positive. Please try again.");
}
Null Pointer Access Variable Can Only Be Null At This Location
Apr 16, 2014I'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?
Another Null Pointer Exception
Aug 14, 2014 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]....
How To Fix Null Pointer Exception Error
May 16, 2014what 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
Aug 6, 2014How 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 RelatedNull Pointer Exception When Trying To Write To File
Aug 14, 2014I'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.
Null Pointer Exception On Initialized Variables?
Oct 10, 2014Take 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]
Moving Circle - Null Pointer Exception
Apr 9, 2014I 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?
Prevent ComboBox From Being Used - Getting Null Pointer Exception
Oct 8, 2014Should 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);
Null Pointer Exception With File I / O And Scanner
Jul 26, 2014I 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] .....
CompareTo Statement - Null Pointer Exception
Apr 16, 2014I 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] ....
Go Fish Program And Null Pointer Exception
Mar 23, 2015I'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!!!
How To Easily Use Graphics
Dec 31, 2014I am attempting to create a n-body simulation using orbital dynamics and Java in school.
I am only in high-school, but I have some programming experience. The logic of this program comes quite easily. My problem is the graphical part, so I was just looking for quick methods to implement graphics.
What I am looking to do, is display objects onto the screen and manipulate their respective x and y coordinates as time pass. I have tried to use BufferedImages and an array of every pixel on the screen, but it quickly becomes extremely hard to draw circles etc. I have also tried the Graphics class and using g.fillOval() etc, but this can also get tedious.
Are there any more efficient methods, libraries etc? And also, how should I use the time variable, a variable that updates everytime the program updates?
JSF :: Java Lang Null Pointer Exception In Webservices
Apr 2, 2014i 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]....
Null Point Exception Error While Calling A Method
Mar 19, 2015I'm trying to call the grade.processFile method from the main method but I'm getting this Error below. I'll post my code which includes the main method and the class underneath the error message:
Exception in thread "main" java.lang.NullPointerException
at java.io.FileInputStream.<init>(FileInputStream.jav a:130)
at java.util.Scanner.<init>(Scanner.java:611)
at MyGrades.processFile(MyGrades.java:49)
at myGradesMain.main(myGradesMain.java:19)
import java.util.Scanner;
import java.io.*;
[code]...
AWT Event Queue Null Pointer Exception While Using JRE 1.7.51 As IE Browser
Feb 17, 2014My 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] ....
Run Time Error As Null Pointer Exception While Compiling
Apr 12, 2015I 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().
Score Board - Constructor Null Pointer Exception
Sep 7, 2014I'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] ....