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- 1
- how to determine when a servelt will unload????Hi -
I have a webpage that utilizes a servlet (written in JBuilder 7 and is
ran under Tomcat 4.0)...is there a way to find out how long of an idle
time is allowed (no calls to the servlet from the client) before the
servlet will be unloaded by Tomcat? And if I can find this out, can I
set this value somehow.
I have tried using the session.setmaxintervaltime but that does not
seem to work.
I would like to be able to kill the servlet after some set amount of
time so that I can run some code in the servelts destory method.
Thanks
- 1
- How to render a JCheckBox on cells of JList?I do it like this:
public class CheckBoxCellRenderer extends JCheckBox implements
ListCellRenderer {
public CheckBoxCellRenderer() {
super();
}
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
if(isSelected)
{
this.setForeground(java.awt.Color.BLUE);
}
this.setEnabled(isSelected);
this.setText("Hello");
return this;
}
However, there is a problem: I can not select or disselect those check box
rendered in the JList.
What wrong?
Thanks.
MaoXuePeng.
- 2
- jndi setup of ldaphi,
I'm trying to load a Postgresql Jdbc3PooledConnection object into my
openldap server on a redhat box :).
what I wanted was a context jdbc/database, and in that a series of
driver references. I have made an entry, but am not sure I've dont it
right though. Can you see what is wrong?
The examples in the web all have lookups of the form
lookup(jdbc/EmployeeDB)
yet mine won't work unless i use ldap like tags as in
lookup("cn=database,cn=jdbc");
firstly i set up jndi properties to connect to the ldap server. (had
to add write permission on redhat box)
<code>
java.naming.factory.initial=com.sun.jndi.ldap.LdapCtxFactory
java.naming.provider.url=ldap://192.168.1.1:389/dc=mtel,dc=co.uk
</code
Then I added the references (had to do this one at a time, modifying
code
lines to add context, then the driver). This i checked with
slapsearch, and
made sure the entries where there. I loaded the driver in a new test
program to make a connection from the driver to test it, so i know it
works.
<code>
Hashtable env = new Hashtable();
Context ctx = new InitialContext();
InitialDirContext dctx = new InitialDirContext();
if(ctx == null )
throw new Exception("JNDI could not create InitalContext
");
//dctx.createSubcontext("cn=jdbc"); ** context 1
//dctx.createSubcontext("cn=database,cn=jdbc"); ** context 2
Jdbc3PoolingDataSource src = new Jdbc3PoolingDataSource(); //
driver
src.setDataSourceName("livedb");
src.setServerName("192.168.254.99");
src.setDatabaseName("livedb");
src.setUser("user1");
src.setPassword("youwish");
src.setMaxConnections(10);
ctx.bind("cn=livetest,cn=database,cn=jdbc", src);
</code>
- 2
- Render .eps in swingDoes anyone have any information on how i would go about rendering .eps
files in swing, whilst preserving the "vector/scalable" property of them?
best regards
Costas
- 3
- OutOfMemory and Swap SpaceI have this strange issue with an Out Of Memory error thrown on a Sun
JVM 1.4.1 residing on a Windows 2000 box.
The Windows boxes is configured to have 4 GB physical RAM out of which
2 GB is available to applications on their server. ( Based on this
article at:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/memory/base/4gt_ram_tuning.asp
)
Out of this 2 GB , we have 3 JVMs of heap size at 768 M. Thich means a
total of 2034 Megs allocated only to Java processes implying a 2048 -
2034 = 14 Megs left for other applications and most importantly swap
space.
I have -verbose:gc logs that tell me that initially a couple of full
GCs happen followed by a monotonically increasing scavenges and just
before the OOM some hectic full GCs happen apparently to reclaim some
memory but never do.
How important is the consideration of Swap Space in troubleshooting
such an error. Since this is a production environment, I just wanted to
have an idea before I go ahead and recommend a decrease in the heap
sizes for this environment.
Your assitance is greatly appreciated.
-Paddy
- 6
- enum: display elements of an enum specified at runtimeHello,
I have the following problem:
I need to perform validation on an input parameter that is a String.
This String has to be one of the values of an enumeration.
The problem is that the enumeration type is not known until runtime - thus
the caller tells me that the concerned enum by specifying its full
qualified name.
e.g.
boolean validateStringOnEnum( String toTest, String
enumFullQualName);
Does anybody know what the code would look like?
Cheers!
- 7
- Blowfish hashDoes anyone know how to do a Blowfish hash in Java? I need
to hash a password
- 7
- JTree sorting ...Is there a simple way to sort tree nodes either by the JTree or its model ?
I can't seem to find anything on the subject.
Thank you in advance,
Benoit
- 9
- Question about Naming ServiceHi everybody,
SITUATION. Two machines with JacORB: each runs a servant of mine.
PROBLEM. I need the two servants to share the same Corba NameServer so
that they can interact.
I tried to run the JacORB naming service on both machines but, at my
best, I get two separate corba "domains" (say, the two servants can't
see each other).
Any tips or documentation or demos about it?
I would appreciate anything, even if from other ORBs.
Thankyou.
- 9
- Repainting and threading - the eternal problem...Hi there folks!
I have a program, with MANY lines of code, so I will not post the
entire program here. However, this is my problem.
I have a GUI program based on swing which contains a JList:
===
this.userTrapList = new JList(this.userTrapListModel);
this.userTrapList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
this.userTrapList.setLayoutOrientation(JList.VERTICAL);
this.userTrapList.addMouseListener(this);
this.userTrapList.setCellRenderer(new MyCellRenderer());
===
As you can see, I also have a custom cell render called
MyCellRenderer:
===
private class MyCellRenderer extends DefaultListCellRenderer {
public static final long serialVersionUID = 1L;
public Component getListCellRendererComponent(JList list, Object
value,
int index, boolean isSelected, boolean cellHasFocus) {
JLabel label = (JLabel) super.getListCellRendererComponent(list,
value, index, isSelected, cellHasFocus);
TSListObject tsl = null;
try {
tsl = (TSListObject)value;
} catch (ClassCastException cce) { }
if (tsl != null && tsl.hasBeenSent()) {
// if tsl has been sent, set background.
label.setBackground(hasBeenSentColor);
}
//// HERE I LEFT SOME CODE OUT ////
return label;
}
}
===
One of the features of the cell renderer is that, once a TSListObject
(which is what the JList contains) flag "hasBeenSend" is true, the
background color is set to green.
What the program does it iterates over the items of the list and sends
them. The class which sends them implements runnable, and here is how
I send them:
===
Enumeration<TSListObject> en = this.userTrapListModel.elements();
while (en.hasMoreElements()) {
TSListObject tmpTSL = en.nextElement();
/* THIS IS WHERE THE SENDING HAPPENS! */
SnmpPDU pdu = tmpTSL.getSnmpPDU();
TrapSenderModel ts = new TrapSenderModel(pdu, session,
dstHost.getText(), spinnerInt.intValue(), new Debug(1));
ts.addObserver(this);
Thread tsThread = new Thread(ts);
tsl.setHasBeenSent(true);
tsThread.start();
try {
tsThread.join();
Thread.sleep(500);
} catch(InterruptedException ie) {
//Catch nothing
}
}
===
As you can see, the actual sending happens when TrapSenderModel's
method run() is executed, which is the same as tsThread.start();
The TrapSenderModel extends Observable and every time it does
send(pdu) (which is not displayed here), it setChanged() and
notifyObservers(pdu).
In my GUI program, which implements Observer, I have an update()
method:
===
public void update(Observable obs, Object obj) {
System.out.println("Update caught!");
this.userTrapList.repaint();
}
===
Okey... Now that we've got the background covered, lets get down to
the problem:
If my JList contains 9 items, and I send them all, the output to
System.out is a nice print of "Update Caught" every 500 milliseconds,
HOWEVER, the background color of the labels do not update until all
items have been sent.
I would like the background of each cell to change momentaneously, as,
if we have a 0.5 second wait between sending every item, and we send
100 items, that means 50 seconds of not showing any change. This will
probably make the user impatient or worried.
I haev tried several methods to get this working, however, I did never
become best friends with SwingWorker and such....
I'm just thinking that, since the sending happens in a thread of its
own, why cannot the GUI update in its own native thread?
What have I missed? I've spent the entire day here and havn't come up
with anything!
I'm greatful for any help I can get (and yes, I've read manuals,
articles, forums, google and so on).
Yours,
Jonas
- 10
- client/serverHi
How can I write a client server where the client download a file from the server?
Vincent
- 10
- Strange servlet exceptionOn Feb 1, 7:35 am, CarloC <email***@***.com> wrote:
> Hi,
> inside my generic servlet I get this error when I call this method:
> 'session.getAttribute' command (line 36):
>
> java.lang.NullPointerException
> at java.util.Hashtable.get(Hashtable.java:336)
> at
> org.apache.catalina.session.StandardSession.getAttribute(StandardSession.java:
> 1024)
> at
> org.apache.catalina.session.StandardSessionFacade.getAttribute(StandardSessionFacade.java:
> 110)
> at workcity.servlet.GenericServlet.checkToken(GenericServlet.java:36)
>
> This is the java code:
>
> HttpSession session = req.getSession();
> ArcUtente vo = (ArcUtente) session.getAttribute(token);
>
> req is a HttpServletRequest object !=null and
> token is a String object != null.
>
> You can help my?
> Carlo
Looking at the JavaDoc for Hastable:
* @throws NullPointerException if the specified key is null
It very well could be token really is null.
Just to verify, try this:
HttpSession session = req.getSession();
if (token == null) { throw new NullPointerException("Token really IS
null!") };
ArcUtente vo = (ArcUtente) session.getAttribute(token);
- 13
- Can't reinstall Tomcat webapp because of log4j.properties lockedI've got a webapp that uses log4j for logging. The log4j.properties
file is in the classes directory of the application. Logging works
fine.
Problem is when I try to (using ANT) redeploy the application. This
first removes the application then installs a new jar.
It appears that Tomcat is unable to remove the log4j.properties file
because it is "in use". (The application has been stopped at this
point). So the new install fails until I manually restart tomcat at
which point the properties file can be deleted and all works fine.
Any ideas of how I can get Tomcat to "release" the properties file.
Is this a bug in log4j = not closing properties file after reading it?
- 16
- JList back colorHello, all !!!
Objective: I've got JList. I want the area inside it, where strings are
shown to be some color. But when I use myJList.setBackground(Color), the
whole list with outside part becomes repainted.
Help me plz.
- 16
- HashSet with complicated objects (fin!)On Sat, 20 Nov 2004 03:34:26 +0000, Tony Morris wrote:
> "Mike" <email***@***.com> wrote in message
> news:email***@***.com...
>> Hey!
>> [dumb question was here]
>> Many thanks.
>>
>> Regards,
>>
>> Mike
>
> The fact that you are talking about a HashSet implies that you aren't doing
> things the right way.
> Specifically, you should be handling types with an interface reference, such
> as a java.util.Set.
>
Yes, sorry, sloppy language. I hate it when I do that. The Set is
declared as a Set but instantiated as a HashSet, as you have shown below.
> Here is an example:
> Set<?> s = new HashSet<?>();
>
> So now you are talking about a Set - the underlying implementation being
> [... now-obvious-seeming explanation deleted for brevity ...]
> that you meet that contract or the consequences are dire (and often
> under-estimate).
>
(sound of penny, probably dislodged by whacking side of head with palm
of hand, dropping into the mechanism)
Yah, gotcha! D'oh.
> Here are some links of interest:
> [useful links elided]
Excellent, thank you!
Thanks also to Bill Brogden for the whack the other way.
Regards,
Mike
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| Author |
Message |
thufir.hawat
|
 Posted: 2004-7-17 11:55:00 |
Top |
java-programmer, hot java
"hot java" sounds so...pornographic? larcenous?
anyhow, suns "hot java browser" is end-of-life, or whatever. I've poked
around a bit and found jazilla, some sort of "ice" java..
anyone use these, or other browsers written in java?
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Index ‹ java-programmer |
- Next
- 1
- Response cache on the application serverIs it a good thing to cache the search result?
The metadata for our system can be as much as 100,000
I am trying to enable the response cache on the web server.
However, I am thinking about the problem i might meet.
When you cache the search result, is it possible the other
person throw the same condiiton and see the same result?
With our system there some security set for each row, so
if this happens there is a security leak.
MD
- 2
- Bound Threads (Re: Process vs Thread: what are the consequences?)On Tue, 13 Nov 2007 16:04:12 +0000, Kenneth P. Turvey wrote:
> Just based on some experimentation I was doing, this doesn't seem to be
> true. I'm running Linux with the Sun JVM, and it didn't map each Java
> thread to a native thread until the Java thread was spending enough time
> executing. I was actually trying to get this mapping (1 to 1) and found
> it impossible to guarantee under Linux with the Sun JVM.
>
> Under Solaris there is the -XX:UseBoundThreads (or something similar) to
> get that behavior, but under Linux no such option exists.
>
> I will freely admit that my experiment could have been flawed, but it
> wasn't behaving as if it was using more than a single native thread. I
> suspect that the article above is out of date.
I hate to followup my own post, but I've been looking at this problem
again and I'm really just unhappy with how it works. Since this can so
easily be solved under Solaris, and Lew (I think?) mentioned that this is
all JVM dependent. I was hoping somebody could point me to a JVM that
runs under Linux that supports the -XX:UseBoundThreads option or something
similar. I want a 1:1 mapping between native threads and Java threads and
I just can't seem to get it.
Does anyone have any idea? (BTW, I checked IBM's JVM).
--
Kenneth P. Turvey <email***@***.com>
- 3
- A basic tomcat questionHi gang, Tomcat's not my area of expertise but I have to get some simple
things set up -- nothing fancy.
I'm having trouble getting classes & packages to work. The setup is Tomcat
5.5.4 & JDK1.5. I can get basic servlets and JSPs to work, but I'm having
trouble with user classes and packages. Here's an example:
tomcat\webapps\ROOT\Test\TestMovie.jsp
----------------------------------------
<#@ page import="testpackage" @>
<html>
<body>
<% Movie m = new Movie("Gone With the Wind", 1936, 19.95); %>
<%= m.title %>
</body>
</html>
tomcat\webapps\ROOT\Test\WEB-INF\classes\testpackage\Movie.java
-------------------------------------------------------------------------
package testpackage;
public class Movie
{
public String title;
public int year;
public double price;
public Movie(String title, int year, double price)
{
this.title = title;
this.year = year;
this.price = price;
}
}
I've googled this & read the documentation, everything seems to say put all
the classes in packages, create a folder for the package under
WEB-INF\classes, and put the class files in the package folder, and that
should do the trick. But I must have something else missing. Any ideas?
Also, I don't know if this is related, but is there a trick to using new
featured of Java 1.5 in a JSP? I can't get the following JSP to compile:
<%@ page import="java.util.*" %>
<html>
<head>
<title>You're breaking my concentration.</title>
</head>
<body>
<% ArrayList<String> s = new ArrayList<String>();
%>
</body>
</html>
It complains about the first < in the scriptlet. Does that have to be
escaped somehow?
TIA,
--D
- 4
- Java Chat Recording.Hi,
A website I use has a chat room and it's chatter-side interface is a Java
application. The comments chatters post come thick and fast and, although
there is a scoll bar, it's no good scrolling down to see comments missed,
as, as soon as a new comment is posted, all the comments scroll up to it.
There is no cut-and-paste/recording facility. As it's possible to scroll
up and down the comments, there must be somewhere where the comments are
held. Would this be just in some sort of video buffer, a
constantly-appended file on my PC's disk drive or just in memory? Is there
any way to record the conversations? Have the output from the Java
application redirected to a file, etc?
Thanks in advance.
Yours,
Gary Hayward.
- 5
- URL in IFRAMELet's say I have a struts action at http://xyz.com/someAction.do and this
URL is referred from one IFRAME via "src" attribute of IFRAME. Is it
possible for me to detect inside someAction.do which page is embedding it in
an IFRAME? How can I do this?
et me put question in a different way, if I refer to Google API with this -
code:
------------------------------------------------------------------------------
<script
src="http://maps.google.com/maps?file=api&v=2.x&key=ABQIAAAAHuQre3TX-ZKoHs97iqelnBQn09xNixTqt4LnUZ12n-xJURxIHRRdLvNa4xtUwCJO0gkyTjCSRjfctQ"
type="text/javascript">
------------------------------------------------------------------------------
How does it know that the request is coming from domain xyz.com? It is not
purely based on the key - if I send same key from another domain, it doesn't
work! So how can I do that? Which header do I use? The referer header is
returned as null!
- manish
- 6
- Error passing Element to web serviceI'm upgrading from WebLogic 6.1 to WebLogic 8.1 SP 4.
We used to specify weblogic.soap.http.SoapInitialContextFactory and
weblogic.soap.encoding.factory to lookup the web service in the client.
Well, the SoapInitialContextFactory and CodecFactory classes are no
longer around. So now I've used clientgen to generate the stubs and
here is my client code:
MyWebService service = new MyWebService_Impl(wsdlurl);
MyWebServicePort port = service.getMyWebServicePort();
Element result = port.processIt(theElement);
However, I get the following error calling processIt:
java.rmi.RemoteException: web service invoke failed:
javax.xml.soap.SOAPException: failed to serialize interface
org.w3c.dom.Element weblogic.xml.schema.binding.SerializationException:
Failed to serialize Document due to the following error
weblogic.xml.stream.XMLStreamException: The local name of an attribute
cannot be null
...
Caused by: weblogic.xml.schema.binding.SerializationException: Failed
to serialize Document due to the following error
weblogic.xml.stream.XMLStreamException: The local name of an attribute
cannot be null
at
weblogic.xml.schema.binding.internal.builtin.DocumentCodec.serialize(DocumentCodec.java:76)
...
Here's the schema and xml file:
<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://myproject.org/myproject_test.xsd"
xmlns:myproject_test="http://myproject.org/myproject_test.xsd"
elementFormDefault="qualified">
<element name="TEST">
<complexType>
<sequence>
<element ref="TEST_ID"/>
</sequence>
</complexType>
</element>
</complexType>
<element name="TEST_ID" type="string"/>
</schema>
<?xml version="1.0" encoding="UTF-8"?>
<TEST xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://myproject_test.xsd"
xsi:schemaLocation="http://myproject.org/myproject_test.xsd"
file:///N:/myproject/metadata/myproject_test.xsd">
<TEST_ID>ABCD1234</TEST_ID>
</TEST>
I've been testing with this bare minimum schema so that I can change
the namespaces and other things easily. The one and only thing that's
made a difference is when I take out the namespace stuff from the xml
file, it does get sent to the server. I.E.:
<?xml version="1.0" encoding="UTF-8"?>
<TEST>
<TEST_ID>ABCD1234</TEST_ID>
</TEST>
However, I can't leave it like that because the server doesn't know
what to do with it. Also, when the server tries to send the response,
it gets the same error as above.
weblogic.xml.stream.XMLStreamException: The local name of an attribute
cannot be null
at
weblogic.xml.babel.adapters.DOMAdapter.adaptAttribute(DOMAdapter.java:113)
at
weblogic.xml.babel.adapters.DOMAdapter.adaptElement(DOMAdapter.java:147)
...
javax.xml.soap.SOAPException: failed to serialize interface
org.w3c.dom.Element weblogic.xml.schema.binding.SerializationException:
Failed to serialize Document due to the following error
weblogic.xml.stream.XMLStreamException: The local name of an attribute
cannot be null
The web service also returns an Element, but it's a different type from
a different schema, which I haven't touched. So the server is having
the same problem as the client.
If I change the web service to receive and return only strings, it
works fine. But I haven't been able to figure out why it won't work
for the Element. Does this sound like a problem with my WebLogic
configuration, the schemas/xml files, the web service, the client? Is
there a way to tell what attribute it is complaining about?
Thanks,
Christy
- 7
- Hibernate305: delete query fails with "must begin with SELECT or FROM"I'm using Hibernate 3.0.5, JDK 1.4.2, and Oracle 9i.
I'm following the Hibernate 3.0.5 docs to build a query to delete rows
from a table. My code looks something like this:
-----------------
String hql = "delete ReqField " +
"where fieldName = :fieldName and value
= :value";
Query query =
sessionFactory.getCurrentSession().createQuery(hql);
query.setString("fieldName", fieldName);
query.setString("value", value);
int deletedRows = query.executeUpdate();
-----------------
This fails with:
org.hibernate.QueryException: query must begin with SELECT or FROM:
delete [delete ReqField where fieldName = :fieldName and value
= :value]
What is wrong with my query?
- 8
- 9
- Forcing swing gui to be drawnHey, right now I have a program that analyzes an EKG when a button is
clicked. I want to pop up a progress bar in a new frame to show how far
it is, but I'm having problems. I can create the frame, and it will
appear, but it won't draw the progress bar until it is done executing
all of the other commands.
I ahve tried opening the frame with a separate thread, but it resulted
in the same problem. I guess there must be some draw queue that is on a
low priority, but I really have no idea why it isn't working.
Any help would be great... I show this at a science fair in 2 days.
Thanks!
-Thomas
- 10
- Java Native Interface - passing parameter array of different datatypesGreets!
Yesterday I googled for hours to find a tutorial how to call Java
methods from C++ native code. Unfortunately I didn't find anything
useful, the Java JNI documentation doesn't capture the functionality
of the JNI very well.
I want to do the following: I want to call a Java method from C++
code. The Java method has some parameters of different datatypes, like
public static boolean dosomething(int x, long y, String z)
for example. Is there any way to do this? The Call...Methods() take
the method ID and an array of parameters to pass to the function, but:
HOW TO CREATE AN ARRAY OF DIFFERENT DATATYPES???
It's only possible to create a new array calling something like
NewObjectArray() when passing a datatype given.... I think, the only
way to pass parameters of different datatypes from C++ to Java methods
is to create a new class containing all parameters necessary and to
pass the class as the one and only argument.
Any ideas?
Best Regards
Clemens
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]
- 11
- JMF video frame sizeI need to know dimension of the media file played by
javax.media.bean.playerbean.MediaPlayer
I use the code you can see below:
FormatControl formatControl = (FormatControl)
this.mediaPlayer.getControl ("javax.media.control.FormatControl");
VideoFormat videoFormat = (VideoFormat) formatControl.getFormat();
return videoFormat.getSize();
mediaPlayer is known object from another class.
But I get formatControl == null.
It's very very strange, but just one time this code did work.
So I have no idea ... Someone else?
- 12
- put application on server ??!!!!I have developed a java application that can return shortest path by
inputting data.
I would like to integrate this application into web application by putting
into tomcat server so that client can use the application through the
internet.
I am new to web service programming and I just start to learn jsp. I would
like to ask how I can do such implementation?
make my application into a bean ? and use the bean?
Please give me advice and help or references ..
Thousands thanx
- 13
- Parsing a test fileI'm pretty new to Java and have been assigned to parse a log file.
The file is tab delimited. I have several tokens that I need to look
for. I have to find all the rows that have "290" then check a column
within that row. That value must match a pattern. The pattern will be
stored in a db table, so the user can add muliple patterns. That item
will then be placed in a new file.
A good example would be awesome.
Thanks.
- 14
- java 6 used in large companies?hi..
we are a large company considering the move from java 1.4 to either 5
or 6.
at the same we are upgrading to was6 (or maybe jboss 4), we are
interested to learn if there are any major projects on enterprise
level involving java 6 (including the use of it's web services
framework).
- 15
- How to convert Java class to exe files for performance?I have developped a java application (no awt involved) for my school research.
It's basically a scientific calculation program, which has huge loops.
Now it's very slow to run it in java/JIT.
I'd like to know if there are some existing free program to translate java
code(or class) to C code(or exe) since rewrite my code in C will take too long.
Has anyone used samilar converter before? Any suggestion is appreciated.
Thanks,
Wei
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