Why Is Exception Not Thrown When Connection Is Terminated
Jul 27, 2014
Below 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?
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?
I 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)
I 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
I 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?
I 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;
In 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."); }
I got the below exception .how to resolve this .It's receiving the data up to 10 min then suddenly below error happening. I have embedded the source code below
java.net.SocketException: Connection reset at java.net.SocketInputStream.read(Unknown Source) at java.net.SocketInputStream.read(Unknown Source) at sun.nio.cs.StreamDecoder.readBytes(Unknown Source) at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
I have the following unit test that gives me a null pointer exception. The debugger goes to the finally block right after the line that creates a connection factory. Here's the test:
Now, I have got a comment saying I should get the database connection from connection pool. And one more issue is that I have used the function System.getProperty("user.name") to get the username which i have logged in. But this code will be run on Unix which will not support this function. Any function where I can get the windows username. There is a function getUserPrincipal(), but this function returns a NULL. How to resolve this.
I configured a connection pool in tomcat 7. For every database activity I get a connection from the pool. Do I have to close the connection like other regular connection after the database operation is done? If I close the connection will it have any effect on the connection pool?
Trying to run my program after getting rid of code errors (I think) and now it doesn't produce anything but <terminated> in the console window. The produce is suppose to analyse text from a file and produce the percentage of words used
I don't know why but my script gets terminated after bufferedreader gets activiated (Im not done yet). It stops right after the user inputs what kind of movie the want to watch.
#import java.io.*;
public class erichw3 { public static void main(String[] args) throws IOException { BufferedReader type = new BufferedReader(new InputStreamReader(System.in)); BufferedReader movie = new BufferedReader(new InputStreamReader(System.in));
[Code].....
I input 1 and nothing happens. Then I put System.out.println("Hi"); at the end (Not in the if Statements) and after I input it skipped to printing Hi.
My homework assignment is to create a program that reads two military times and then prints out the elapsed time. I've got all that down and ready to go but then the other part of this project is to have it loop until it is terminated manually. So at the end where it asks for a 'Y' or 'N' input answer is where I know i need to implement a do-while loop or switch statement, I'm not sure. how to make the application repeat until told to quit.
I wanted to Start Java Programming on Eclipse.. I ran into this problem when trying to run Eclipse, having installed latest Version.. I tried Googling The issue but didnt Found out answers For the same.
Basically I'm trying to compute the standard deviation for a set of numbers and I'm using previously know data to compute this. The data I'm working with is here (note all of this is fake as its for an assignment):
Next this is the code that I know is producing the error:
/** * Pass in original data from files, and pass in computed grades as arraylist. this returns all of the standard deviations to be printed */ public static ArrayList calcStandDev(String data1[], ArrayList<Double> grades, ArrayList<Integer> averages) { double standDev = 0; int j = 0; //gets rid of first element in string array, makes processing MUCH easier String[] data = Arrays.copyOfRange(data1, 1, data1.length);
[Code] ....
Look for the line with all the ***'s, it is producing the "java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Integer".
The reason I dont undersand why its producing this error is because temp.get(i) should be a integer - averages.get(i) (is type double), I do believe automatic up casting is present here making them both a double then I multiply it by itself producing a double? I dont understand where the casing is occurring. And just incase you want the formula I'm using for standard deviation here it is:
I need to create a simply application that would display the results of two dice thrown five times and the total of those results. This is shown below in the attached file.
The problem is, I have a do-while loop that loops 6 times. Inside the loop, I have 2 random.nextInt(5) that generate random numbers. But how can I output the total? How can I make a variable equal to the sum of the two random numbers if the two random numbers are located inside a do-while loop?
Attached below is also the code I have thus far.
(Attached below is both files: what it needs to look like, and what it currently looks like)
I was giving a quick skim to some tutorials on the internet where I have found the exception that is handled is also declared in the throws clause of the method wrapping the try-catch block. For a code representation consider the following:
public void methodName() throws IOException { try { ... } catch (IOException ex) { .... TODO handle exception }
Right, so I got this program. It takes input from the user and assigns it to fields on an object. But, it's meant to check the users input. If the user enters bad input, it's supposed to throw this exception. For each of these exceptions, theres a class specifically for it.
public class PayrollDemo { public static void main(String[] args) { Payroll pr = new Payroll ("Test Name", 234); System.out.println("Current Employee Information. "); System.out.println("Name: " + pr.getName()); System.out.println("ID: " + pr.getID()); System.out.println("Hourly Pay Rate: " + pr.getHourlyPayRate());
[Code] ....
And this is the exception class.
public class InvalidNameException extends Exception { /** No-arg constructor */ public InvalidNameException() { super("Invalid name"); } }
PayrollDemo.java:43: error: cannot find symbol InvalidNameException.InvalidNameException(); ^ symbol: method InvalidNameException() location: class InvalidNameException 1 error
It's just meant to tell the user that they entered an invalid value, which would mean if they entered an empty string instead of a name.
I was wondering if I could take the following code and somehow put the connection to database in it's own class without the "public static void main(String[] args)" method. That way I could call it anytime i want to open a connection to the database.
Java Code:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class Sample { public static void main(String[] args) throws ClassNotFoundException
I am new to EJB; I am writing EJB (3.1) program in JBoss 7.1 - I am using MySQL DB with JPA. While executing the program, I am facing the Generic JDBCException: Could not open connection. It is happening only for certain tables in the database; but NOT for all tables. My code is able to access few of the tables in the same database. Here is my full stack trace: -
Exception in thread "main" javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:166) at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:230) at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:304) at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:190) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
I'm using JSF framework. I can let Netbeans to create the persistence unit and hardcodes connection parameters into the persistence.xml file or i can use resource tag in context.xml file or using another file like property file or class for holding connection parameters like username and password; what is the most secure way or expert way to use connection properties in my app or there is no difference?
