Catching this exception
Hi
I have created a simple client server program . In the Client i give the server ip/name and port number in command line... but when i try to run the client on a port on which the server is not running .. the following message is generated....
C:\Program Files\Java\jdk1.5.0_02\bin>java echocli darkside 1000
Exception in thread "main" java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:364)
at java.net.Socket.connect(Socket.java:507)
at java.net.Socket.connect(Socket.java:457)
at java.net.Socket.<init>(Socket.java:365)
at java.net.Socket.<init>(Socket.java:207)
at echocli.main(echocli.java:51)
C:\Program Files\Java\jdk1.5.0_02\bin>I have written this to catch the exception but ...the error statement is not printed.....
catch(ConnectException e1)
System.out.println("\n No server running on that port " );
}whats wrong...why is it not catching this exception........
I find it odd that your program compiled clean since Socket.connect throws IOException. Did you catch the IOException first and ignore it? If so that's why your ConnectException never got caught. You must catch exceptions in the order of most specific to least specific. So for a Socket.connect that means
ConnectException
SocketException
IOException.
Similar Messages
-
Why do I need to catch this exception?
Hello all
This is a question about exception handling. I have to build a diary application that lets you save reminders on particular dates using xml. Just to make it a little tougher, I was not allowed to use the Calendar class. This is the code I wrote:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.text.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
import java.io.*;
import org.w3c.dom.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import static java.lang.Math.*;
public class CalendarAssignment extends JFrame implements ActionListener
int MonthLength [] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
public JButton [] days = new JButton[43];
private JLabel lbl, reminderlbl;
private JPanel top, grid, remindercenter, reminderbottom;
private JFrame reminderframe;
private JTextField year1, reminderinput, dayno;
private JComboBox months;
private Container container;
private JButton fetch, save, cancel;
private Document doc;
private File file;
private Node node;
private String year, month, day;
public static void main( String[] args ) {
CalendarAssignment c = new CalendarAssignment( );
c.setSize( 400, 300 );
c.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
c.show( );
public CalendarAssignment( ) {
int CurrentYear, CurrentMonth;
String YearString, MonthString, Now;
Date today;
container = getContentPane( );
container.setLayout( new BorderLayout( ) );
SimpleDateFormat DateFormatter;
DateFormatter = new SimpleDateFormat( "MM.yyyy" );
today = new Date( );
Now = DateFormatter.format( today );
MonthString = Now.substring( 0,2 );
YearString = Now.substring( 3,7 );
CurrentMonth = Integer.valueOf( MonthString );
CurrentYear = Integer.valueOf( YearString );
top = new JPanel( );
String [] items = { "January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November",
"December" };
months = new JComboBox( items );
months.setEditable( false );
months.setSelectedIndex( CurrentMonth - 1 );
year1 = new JTextField( );
year1.setText( YearString );
year1.setEditable( true );
year1.setHorizontalAlignment( year1.CENTER );
fetch = new JButton( "Fetch Month" );
fetch.addActionListener( this );
top.setLayout( new GridLayout( 1, 3, 20, 0 ) );
top.add( months );
top.add( year1 );
top.add( fetch );
grid = new JPanel( );
grid.setLayout( new GridLayout( 7, 7, 0, 0 ) );
String [] week = { "Mon", "Tue", "Wed", "Thur", "Fri", "Sat", "Sun" };
for ( int a = 0; a < 7; a ++ ) {
JLabel lbl = new JLabel( week[a], JLabel.CENTER );
grid.add( lbl );
for ( int i = 0; i < 42; i ++ ) {
days[i] = new JButton( );
grid.add( days[i] );
days.addActionListener( this );
DrawCalendar( CurrentMonth, CurrentYear );
container.add( top, BorderLayout.NORTH );
container.add( grid, BorderLayout.CENTER );
private void DrawCalendar( int SelectMonth, int SelectYear ) {
int DisplayMonthLength, Buttons;
String ButtonID = "";
int OffSet = MonthStart( SelectMonth, SelectYear );
DisplayMonthLength = MonthLength [SelectMonth - 1];
if ( SelectMonth == 2 )
DisplayMonthLength += LeapYear( SelectYear );
for ( Buttons = 1; Buttons < 43; Buttons ++ ) {
if ( ( Buttons <= OffSet ) || ( Buttons > ( DisplayMonthLength + OffSet ) ) ) {
ButtonID = "";
days[Buttons-1].setEnabled( false );
else {
ButtonID = Integer.toString( Buttons - OffSet );
days[Buttons-1].setEnabled( true );
days[Buttons-1].setLabel( ButtonID );
grid.add( days[Buttons-1] );
private int LeapYear( int year ) {
int FourHundred, OneHundred, Fourth;
FourHundred = year % 400;
OneHundred = year % 100;
Fourth = year % 4;
if( ( ( FourHundred == 0 ) ) || ( ( OneHundred != 0 ) && ( Fourth == 0 ) ) )
return ( 1 );
else
return ( 0 );
private int MonthStart( int Month, int Year ) {
int OffSet, LastMonths, BeforeOrAfter, Years;
int AllDays = 0;
int YearDays = 365;
int YearMonths = 12;
BeforeOrAfter = Year - 2006;
Years = abs( BeforeOrAfter );
if( BeforeOrAfter != 0 )
BeforeOrAfter = BeforeOrAfter / Years;
switch( BeforeOrAfter ) {
case 1:
for( int a = 2006; a < Year; a ++ ) {
AllDays += YearDays + LeapYear( a );
AllDays += LastMonthsCalc( Month, Year );
break;
case -1:
for( int a = 2005; a > Year; a -- ) {
AllDays += YearDays + LeapYear( a );
for( LastMonths = YearMonths; LastMonths >= Month; LastMonths -- ) {
AllDays += MonthLength[LastMonths - 1];
if( LastMonths == 2 )
AllDays += LeapYear( Year );
break;
default:
if( Month > 1 )
AllDays += ( LastMonthsCalc( Month, Year ) );
OffSet = AllDays % 7;
if( BeforeOrAfter ==( -1 ) )
return( 6 - OffSet );
else if( OffSet > 0 )
return( OffSet - 1 );
else
return( 6 );
private int LastMonthsCalc( int Month, int Year ) {
int Counter;
int days = 0;
for( Counter = 1; Counter < Month; Counter ++ ) {
days += MonthLength[Counter - 1];
if( Counter == 2 )
days += LeapYear( Year );
return( days );
public void CreateReminder( String buttonID, String yearID, String monthID ) {
reminderframe = new JFrame( );
reminderlbl = new JLabel( );
reminderframe.setLayout( new GridLayout( 2, 1, 0, 0 ) );
remindercenter = new JPanel( );
reminderlbl = new JLabel( "Please type in reminder to be saved for " + buttonID + " " + monthID + " " + yearID + ":", JLabel.CENTER );
reminderinput = new JTextField( 30 );
reminderinput.setHorizontalAlignment( reminderinput.CENTER );
reminderinput.setEditable( true );
remindercenter.setLayout( new GridLayout( 2, 1, 0, 0 ) );
remindercenter.add( reminderlbl );
remindercenter.add( reminderinput );
reminderbottom = new JPanel( );
save = new JButton( "Save" );
save.addActionListener( this );
cancel = new JButton( "Cancel" );
cancel.addActionListener( this );
dayno = new JTextField( buttonID );
dayno.setEditable( false );
dayno.setEnabled( false );
dayno.show( false );
reminderbottom.setLayout( new FlowLayout( ) );
reminderbottom.add( save );
reminderbottom.add( cancel );
reminderbottom.add( dayno );
reminderframe.setSize( 500, 75 );
reminderframe.add( remindercenter );
reminderframe.add( reminderbottom );
reminderframe.pack( );
reminderframe.show( );
public void SaveReminder( String dayID, String yearID, String monthID ) throws Exception {
file = new File( "Diary.xml" );
doc = DocumentBuilderFactory.newInstance( ).newDocumentBuilder( ).parse( file.toURL( ).toString( ) );
String year = yearID;
String month = monthID;
String day = dayID;
//System.out.println( year );
//System.out.println( month );
//System.out.println( day );
CreateEntry( doc.getDocumentElement( ) );
writeXmlFile( );
public boolean CreateEntry( Node node ) {
Node searchNode;
searchNode = getYear( node );
if( searchNode == null ) {
Element newNode = doc.createElement( "Year" );
searchNode = node.appendChild( newNode );
newNode.setAttribute( "Id", year );
node = searchNode;
searchNode = getMonth( node );
if( searchNode == null ) {
Element newNode = doc.createElement( "Month" );
searchNode = node.appendChild( newNode );
newNode.setAttribute( "Id", month );
node = searchNode;
searchNode = getDay( node );
if( searchNode == null ) {
Element newNode = doc.createElement( "Day" );
searchNode = node.appendChild( newNode );
newNode.setAttribute( "Id", day );
node = searchNode;
String entry = reminderinput.getText( );
Node textNode = doc.createTextNode( entry );
node.appendChild( textNode );
return true;
private Node getYear( Node node ) {
node = node.getFirstChild( );
while( node != null ) {
if(node.getNodeName( ).equals( "Year" ) && String.valueOf( node.getAttributes( ).item( 0 ).getNodeValue( ) ) == year )
return node;
node = node.getNextSibling( );
return null;
private Node getMonth( Node node ) {
node = node.getFirstChild( );
while( node != null ) {
if( node.getNodeName( ).equals( "Month" ) && String.valueOf( node.getAttributes( ).item( 0 ).getNodeValue( ) ) == month )
return node;
node = node.getNextSibling( );
return null;
private Node getDay( Node node ) {
node = node.getFirstChild( );
while( node != null ) {
if( node.getNodeName( ).equals( "Day" ) && String.valueOf( node.getAttributes( ).item( 0 ).getNodeValue( ) ) == day )
return node;
node = node.getNextSibling( );
return null;
private void writeXmlFile( ) throws Exception {
Source source = new DOMSource( doc );
Result result = new StreamResult( file );
Transformer xformer = TransformerFactory.newInstance( ).newTransformer( );
xformer.setOutputProperty( OutputKeys.INDENT,"yes" );
xformer.setOutputProperty( OutputKeys.DOCTYPE_SYSTEM,"Diary.dtd" );
xformer.transform( source, result );
public void actionPerformed( ActionEvent e ) {
String IDButton = e.getActionCommand( );
String IDYear = year1.getText( );
Object IDMonthObj = months.getSelectedItem( );
if( e.getSource( ) == fetch ) {
String YearText = year1.getText( );
int YearNumber = Integer.valueOf( YearText );
int MonthsIndex = months.getSelectedIndex( ) + 1;
DrawCalendar( MonthsIndex, YearNumber );
else if( e.getSource( ) == cancel ) {
reminderframe.hide( );
else if( e.getSource( ) == save ) {
String IDDay = dayno.getText( );
String IDMonth = String.valueOf( IDMonthObj );
SaveReminder( IDDay, IDYear, IDMonth );
else {
String IDMonth = String.valueOf( IDMonthObj );
Toolkit.getDefaultToolkit( ).beep( );
int n = JOptionPane.showConfirmDialog( null, "Set reminder on this date?", "Question", JOptionPane.YES_NO_OPTION );
if( n == JOptionPane.YES_OPTION ) {
CreateReminder( IDButton, IDYear, IDMonth );
If you compile it, you will realise that I get an error about exception handling. My lecturer gave me an example code of how to do the same thing without using a GUI:
import javax.xml.parsers.*;
import org.xml.sax.*;
import java.io.*;
import java.util.*;
import org.w3c.dom.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
public class CallDOM
Document doc;
File file;
Scanner input;
int year, month, day;
String currentYear, currentMonth;
public static void main(String args[]) throws Exception
CallDOM cd=new CallDOM();
CallDOM() throws Exception
file=new File("Diary.xml");
//create DOM from file
doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(file.toURL().toString());
input=new Scanner(System.in);
System.out.println("1) Create entry");
System.out.println("2) Read entry");
System.out.println("3) Show Diary");
System.out.println("4) Quit");
int choice=input.nextInt();
while(choice!=4)
switch(choice)
case 1: GetDate();CreateEntry(doc.getDocumentElement());break;
case 2: GetDate();ReadEntry(doc.getDocumentElement());break;
case 3: ShowDiary(doc.getDocumentElement());
System.out.println("1) Create entry");
System.out.println("2) Read entry");
System.out.println("3) Show Diary");
System.out.println("4) Quit");
choice=input.nextInt();
writeXmlFile();
public void GetDate()
System.out.println("Enter date (dd mm yyyy)");
day=input.nextInt();
month=input.nextInt();
year=input.nextInt();
public boolean ReadEntry(Node node)
node = getYear(node);
if(node==null) return false;
node = getMonth(node);
if(node==null) return false;
node = getDay(node);
if(node==null) return false;
node = node.getFirstChild();
while(node!=null)
System.out.println(node.getNodeValue().trim());
node=node.getNextSibling();
return true;
public boolean CreateEntry(Node node)
Node searchNode;
searchNode = getYear(node);
if(searchNode==null)
Element newNode = doc.createElement("Year");
searchNode = node.appendChild(newNode);
newNode.setAttribute("Id",Integer.toString(year));
node = searchNode;
searchNode = getMonth(node);
if(searchNode==null)
Element newNode = doc.createElement("Month");
searchNode = node.appendChild(newNode);
newNode.setAttribute("Id",Integer.toString(month));
node = searchNode;
searchNode = getDay(node);
if(searchNode==null)
Element newNode = doc.createElement("Day");
searchNode = node.appendChild(newNode);
newNode.setAttribute("Id",Integer.toString(day));
node = searchNode;
System.out.println("Enter Text");
String entry=input.next();
entry+=input.nextLine();
Node textNode = doc.createTextNode(entry);
node.appendChild(textNode);
return true;
public void ShowDiary(Node node)
Stack<Node> stack=new Stack<Node>();
Node child;
stack.push(node);
while(!stack.empty())
node = stack.pop();
if(ProcessNode(node))
child = node.getLastChild();
while(child!=null)
stack.push(child);
child = child.getPreviousSibling();
private boolean ProcessNode(Node node)
if(node.getNodeName().equals("Year"))
currentYear=node.getAttributes().item(0).getNodeValue();
if(node.getNodeName().equals("Month"))
currentMonth=node.getAttributes().item(0).getNodeValue();
if(node.getNodeName().equals("Day"))
System.out.print(node.getAttributes().item(0).getNodeValue()+"/"+
currentMonth+"/"+currentYear+": ");
node=node.getFirstChild();
while(node!=null)
System.out.println(node.getNodeValue().trim());
node=node.getNextSibling();
return false;
return true;
private Node getYear(Node node)
node=node.getFirstChild();
while(node!=null)
if(node.getNodeName().equals("Year")
&& Integer.valueOf(node.getAttributes().item(0).getNodeValue())==year)
return node;
node = node.getNextSibling();
return null;
private Node getMonth(Node node)
node=node.getFirstChild();
while(node!=null)
if(node.getNodeName().equals("Month")
&& Integer.valueOf(node.getAttributes().item(0).getNodeValue())==month)
return node;
node = node.getNextSibling();
return null;
private Node getDay(Node node)
node=node.getFirstChild();
while(node!=null)
if(node.getNodeName().equals("Day")
&& Integer.valueOf(node.getAttributes().item(0).getNodeValue())==day)
return node;
node = node.getNextSibling();
return null;
private void writeXmlFile() throws Exception
Source source = new DOMSource(doc);
Result result = new StreamResult(file);
Transformer xformer = TransformerFactory.newInstance().newTransformer();
xformer.setOutputProperty(OutputKeys.INDENT,"yes");
xformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM,"Diary.dtd");
xformer.transform(source, result);
}My question is, why does the exceptions in the example code not need to be caught? And why do I have to catch the exceptions in my code? Several exceptions are thrown in the example code, but there is no catch statement.
Thanks for any advice!!Since your question didn't come with any relevant details, and since you have huge steaming piles of irrelevant code, all I can give is a general answer to "Why do I need to catch this exception?"
[url http://java.sun.com/docs/books/tutorial/essential/exceptions/index.html]Exception tutorial at http://java.sun.com/docs/books/tutorial/essential/exceptions/index.html
Here's a quick overview of exceptions:
The base class for all exceptions is Throwable. Java provides Exception and Error that extend Throwable. RuntimeException (and many others) extend Exception.
RuntimeException and its descendants, and Error and its descendants, are called unchecked exceptions. Everything else is a checked exception.
If your method, or any method it calls, can throw a checked exception, then your method must either catch that exception, or declare that your method throws that exception. This way, when I call your method, I know at compile time what can possibly go wrong and I can decide whether to handle it or just bubble it up to my caller. Catching a given exception also catches all that exception's descendants. Declaring that you throw a given exception means that you might throw that exception or any of its descendants.
Unchecked exceptions (RuntimeException, Error, and their descendants) are not subject to those restrictions. Any method can throw any unchecked exception at any time without declaring it. This is because unchecked exceptions are either the sign of a coding error (RuntimeException), which is totally preventable and should be fixed rather than handled by the code that encounters it, or a problem in the VM, which in general can not be predicted or handled. -
Not able to catch the exception
Hi,
I'm trying to run an ADF page (Test.jspx) . The only page content I have is an embedded BI report.
I have used a report executable in my page definition.
A sample code snippet is:
<executables>
<biContent id="biExecBinding1" connectionId="TMBIPresentationServerConn" path="/shared/TMSharedFolders/MOT_SalesAccount" type="biReportContent" xmlns="http://xmlns.oracle.com/bi/report/bindings">
</executables>
Here TMBIPresentationServerConn is the name of the connection of the BI Server.
If BI Server is down, on running my page , an exception is being thrown by the framework.
I want to catch this exception and perform my own logic, but since i am using a binding context for report , i am not able to catch this exception.
Could you please let me know how can i catch the exception if BI is down?
Thanks
Nutan(as I suspected from your first post)
You are using a version of JDeveloper that isn't available to the general public, and are asking about it on a public forum. You should use the internal Oracle forum - I don't know the URL, because I am one of the unwashed general public ;)
John -
Hi,
Sometimes the load request for an xml fails(timeout maybe)
and a message "unable to load data" is displayed in the flash
player on the mobile phone, how could I catch this exception to
manage the error/exception instead the message was shown???
I have tried the try-catch statement, but it seems that it
doesnt catch this kind of errors, does it?
RegardsI undestand the issue. The error message is displayed through
the device OS default message API . You should consider switching
your data from XML to value pairs (XML files are more cpu intensive
and usually cause more problems). -
How to catch ALL Exception in ONE TIME
I'm explain my issue:
I'm making a program with Class, Swing, Thread ...
Then all action I do on my graphical application, I use a new thread, well
I want to capture in my Startup programs, all unknow exception and then, I display it with a JOptionPane for example
In fact, I want to do something like Eclipse, when it crash, I capture the error
Could you help me ? Tell me the best way to do that ?
This is an exemple
FILE: Startup.java
class Startup{
public static main (String args[]){
try{
new Main();
}catch(Throwable e){
//Message d'erreur fenetre
FILE: Main.java
class Main{
Main(){
init_action();
void init_action(){
mybutton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
Thread th=new Thread(){
public void run(){
int a = 1 / 0;
th.start();
Well, in this example I want to capture the Divide By 0, I use the Throwable Exeption, in order to be sure I catch all unknow exeption
Then, a good job, is to put throws Throwable in all function
but Thread, and ActionPerformed ... could not implement it
How to put this exception and jump it to Startup Program ?I already do that, what can I do for improving capture ?
That's impossible ... It will be a great idea to make a Redirection of Error to a Exception class in futur version
For example, when an unknow error arrive, don't show it on console and crash ... but run a class redirector exception, and magic, it show you a beautiful error warning, and stop properly the programme ...
I put an error class, and put try {] catch {} everywhere, and run my exception class,
this class detect the error exception and run a properly beautiful and clear french message (I'm french :d)
Well, If you have the BEST other idea, tell me, I read your message with a lot of regard
see you soon
bye -
Best Practice: JavaFX pattern for "Catching all Exceptions"
Hi,
what is on the current JavaFX Standard the best way to catch all Exceptions (centralized) within my JavaFX application...
I read thread outside this Oracle Forum who recommend following:
1. Thread.setDefaultUncaughtExceptionHandler(new MyExceptionHandler());
--> catch all runtime exceptions
2. http://stackoverflow.com/questions/12318861/javafx-2-catching-all-runtime-exceptions
--> Implementing some source code who wrap the current GUI thread...
3. I read something like:
"JavaFX exception handling is almost identical to that in Java, apart from the fact that checked exceptions are handled in the same way as unchecked exceptions. This is good news for most Java programmers moving to JavaFX because you are no longer obliged to catch and handle exceptions."
Sounds very good! But where/how can I do this ???
Edited by: wschele on 19.02.2013 04:58
Edited by: wschele on 19.02.2013 05:16No recommendation whats the best way to do it?
Catching each Exception in different layers is boring ! :-( -
Catching the exception thrown in a java class on a JSP front end
I have a web service created in JAVA.. The modules throw certain exceptions and i am having auto generated JSP created from the WSDL's , which i can obviously edit. i want to catch these exceptions in this JSP page.. Any clue how to do this?
Thanks.Nee333 wrote:
I have a web service created in JAVA.. The modules throw certain exceptions and i am having auto generated JSP created from the WSDL's , which i can obviously edit. i want to catch these exceptions in this JSP page.. Any clue how to do this? It is not possible to catch the Exception in a JSP. You can however put any logging or even an if statement into your JSP to display the error or control the flow based on the error. -
How to get details about Exception catched in Exception branch of the Block
Hello Experts,
Is it possible to get details about Exception catched in Exception branch of the Block in Integration Process (BPM)?
In the Exception branch System Error is catched, but from time to time different type of System Errors are happening during sync call to WebService - Connection Timeout, Connection Refused, UnknownHost, etc.
So the task is somehow to map the type of System Error to the response. I was trying to create a mapping using as source the message which is coming from the Adapter after the sync call, but the mapping is failing with "No Source Payload" error.
Maybe the description is somewhere in Header or Dynamic configuration?
Or it is possible to access it somehow with JAVA-maping?
Thanks for your help!Hey,
the message from the exception can be utilized by using alerts(in order to mail,sms r fax). but otherwise its not possible using mappings or container.
check this link for alert configuration.
/people/michal.krawczyk2/blog/2005/09/09/xi-alerts--step-by-step -
SOAP-XI-RFC sync without BPM scenario: How to catch timeout exception in PI
Hi all
I made a scenario where a Webservice request was placed via XI to RFC in CRM.
This is all done without BPM.
Now the request came up that I have to handle undhandled exceptions from RFC such as Fatal Error, Dump in CRM etc in PI so that customer can get the idea of what happend in the Backend rather PI failing in the monitoring. I did that in CRM by catching all the exception and sending a common error message to PI.
But another requirement is to handle Message Timeout of the RFC in PI for e.g. If the request goes to the RFC and due to the volume of the data, it gets Timed Out then neither PI nor CRM can handle this and it results in PI failing to catch this excpetion.
I tried Fault message type but that does not help either.
Can I get some expert advice.
Regards
NainaInclude your Send_to_RFC step inside a Block...have a deadline branch for this and an Exception Branch....in deadline branch have control step (thro Exception)....in Exception Branch have a Mapping and a Send Step....this mapping will produce a message (define separate DT for this) having constant values (like timeout occured message)
If you are fine with alert message...then instead of Mapping and Send step in Exception include a Control Step (thro alert)....alert message can be "timeout occured in receiving RFC response"
Regards,
Abhishek. -
Catching an exception in an JSF page
Hi,
I have made the following example:
In my jsf page I have:
<a4j:commandButton id="save" action="#{settings.save}"
reRender="attributes" />
<h:outputLabel value="Save" for="save" />
<table width="100%" cellpadding="0" cellspacing="0">
<!--
<tr>
<td> If exception occurs add extra buttons here for more actions
</td>
</tr>
-->
<tr>
<td><ui:include src="/attributes.xhtml">
<ui:param name="parent" value="#{settings}" />
</ui:include></td>
</tr>
</table>
In SettingsBean.java
public void save() throws exception
try
doSomething();
catch(Exception e)
// catch the exception here and send it back to the jsf page????
I want to be able to catch the exception when it occurs in my jsf page. If the exception arrises I want to add some extra buttons.
Any ideas how to resolve this?
Thanks in advanceJSF does not work like JSP, even when using JSP with JSF, in that the execution is decoupled from the page being processed. So you cannot catch exceptions in JSF views.
Assuming I have sufficiently confused you now, let me give you some ideas as to how to handle your situation. The usual way this is handled is to register a message when an exception occurs which are then displayed by <h:messages> or <h:message> components.
However, this does not appear to be suitable for your purpose as you require specialized output when the exception occurs. So you could store a flag (or even the exception itself) in a backing bean and use the rendered property of all components to conditionally display your buttons. BUT you will need to take care that the dynamic value of the rendered property will be the same on the subsequent request or the actions for the buttons will not be queued. -
Catching an exception thrown from another thread
I have a SocketServer that creates new threads to handle incoming clients. If one of the threads throw a SQLException is it possible to catch that exception in the SocketServer that created that thread.
I tried implementing this code and I cannot get the server to catch an exception thrown in the thread. Are my assumptions correct?
I was reading something about Thread Groups and implementing an uncoughtException() method, but this looked like overkill.
Thanks for your time!
Some Example code would be the following where the ClientThread will do a database query which could cause an SQLException. I'd like to catch that exception in my Socket Server
try
new ClientThread( socketServer.accept() , host, connection ).start();
catch( SQLException e )
System.out.println( "DataSource Connection Problem" );
e.printStackTrace();
}hehe, why?
The server's job is to listen for an incoming message from a client and pass it off to a thread to handle the client. Otherwise the server will have to block on that incoming port untill it has finished handling the client and usually there are many incoming clients continuously.
The reason I would want to catch an exception in the server based on the SQLException thrown in the thread is because the SQLException is usually going to be due to the fact the datasource connection has become unavalable, or needs to be refreshed. This datasource connection is a private variable stored in the socket server. The SocketServer now needs to know that it has to refresh that datasource connection. I would normally try to use somesort of flag to set the variable but to throw another wrench into my dilemma, the SocketServer is actually its own thread. So I can't make any of these variables static, which means I can't have the thread call a method on teh socket server to change the status flag. :)
I guess I need implement some sort of Listener that the thread can notify when a datasource connection goes down?
Thanks for the help so far, I figured java would not want one thread to catch another thread's exceptions, but I just wanted to make sure. -
Catching an exception within a JSP
Hi all,
I need to catch an exception in a JSP before the errorPage handles it. Have tried with try-catch but it seems like the exception is thrown to the errorPage anyway. Do you know of any technique to handle this.
In other words: I would like to specify program logic for one exception within the JSP itself. Let us say Customer.Authenticate() throws an Exception when the given e-mail is not included in customer-DB. I would like to append logic instead of being redirected to errorPage.
Anyone done this, can it even be done?
,ChrI would try keeping the error page as it is and still adding the logic in the catch block. If that does not help, then remove the error page and use <jsp:forward> (after your logic) in the catch block to explicitly go to the error page.
or if you want to process that logic anyways in case of an exception, try adding your logic in the finally block. -
HOW I CAN CATCH AN EXCEPTION??
HI FRIENDS
I HAVE A PROBLEM
I AM USING THIS CODE
try
fileTemplate=fileReader(TemplatePath);
catch (FileNotFoundException ioex)
where filereader is a function to read files.
but on complining i am getting this error
exception java.io.FileNotFoundException is never thrown in the body...
CAN ANY BODY HELP ME????Well, have you forgotten some "new" ??
your piece of code is simply method call fileReader(templatepath) , and a reference.
And even there, FileNotFoundException isn't thrown at instantiation, you can make
File f = new File("nonexistingpath_or_file");
The FNF Exception comes when you try to open the file, or try to read from, so the compiler tells you that this Exception will never occur in your statement. -
Write and read txt files and catch the exceptions
hey everyone, im in a bit of a bind. im trying to set up this try catch statement. here is what i have for code so far.
import java.util.Scanner;
import java.io.*;
public class Warning
// Reads student data (name, semester hours, quality points) from a
// text file, computes the GPA, then writes data to another file
// if the student is placed on academic warning.
public static void main (String[] args)
int creditHrs; // number of semester hours earned
double qualityPts; // number of quality points earned
double gpa; // grade point (quality point) average
String line, name, inputName = "students.dat";
String outputName = "warning.dat";
try
Scanner FileScan1 = new Scanner (new File("students.dat"));
// Set up scanner to input file
// Set up the output file stream
// Print a header to the output file
outFile.println ();
outFile.println ("Students on Academic Warning");
outFile.println ();
// Process the input file, one token at a time
while (FileScan1.hasNext())//there is another line...
{ // Get the credit hours and quality points and
// determine if the student is on warning. If so,
// write the student data to the output file.
// Close output file
catch (FileNotFoundException exception)
System.out.println ("The file " + inputName + " was not found.");
catch (IOException exception)
System.out.println (exception);
catch (NumberFormatException e)
System.out.println ("Format error in input file: " + e);
}I am pretty sure the layout is good to go, but first and foremost that try statement is hanging me up. Could someone give me some suggestions about how i should set this up.
i want to read in this students.dat file, then output another file called warning.dat.
Thanks i really appreicate the help.no, i was really hoping to just see if the way it is
set up it will be doable, that way i wouldn't be
working on code that was impossiable to sort through
properlyFair enough.
One thing I'd suggest is that if you're really basically only going to be printing the exceptions, and since that is the top-level method (main) --
I'd instead just add some "throws" clauses to main, get rid of the try/catch stuff, and just let the VM handle the exceptions for you. It will print them, just like you're doing, except that it will also print the stack traces, which you are not doing.
If you're going to handle exceptions, it's better to actually do something about them rather than just print them - otherwise you might just as well let the runtime do that for you. -
This exception is never thrown from the try statement body
try {
SimpleFileReader.openFileForReading("fileName.text");
} catch (FileNotFoundException fnfe) {
System.out.println("");
}This is part of a method, if that helps. In Eclipse I get the error message "Unreachable catch block for FileNotFoundException. This exception is never thrown from the try statement body." I saw another post similar to this one, but it's not quite clear what the solution is. Could anyone clarify for a beginner?
ThanksIt actually does if the file it's opening is not really a text file, or if it's read-protected. Or is that where I'm going wrong? I'm just trying to open the file's name(already in the field) and know that it is .text or will return the error.
Edited by: meme_kun_345k on Jan 15, 2008 7:18 PM
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