FailUTF8Conv problem !
Hi,
I am getting this exception while getting records from the oracle database.
java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
Is there anyone know that how can resolve this problem ?
thanks in advance,
bregoty
I don't know much about the topic in question, but in general, you'll stand a better chance of getting help if you provide more details.
What does your code look like? What's are the characters in question? What's the complete stack trace? etc. etc.
Similar Messages
-
Problem in Database convertion from US7ASCII to UTF8
Hi,
We are facing the following problem while converting the database from US7ASCII to UTF8:
We have recently changed the database character set from US7ASCII to UTF8 for the internationalization
purpose. We ran the Character set scanner utility and it did report that some data may pose problems.
We followed the the below mentioned process to convert into UTF8 -
1) alter database character set utf8
2) alter database national character set utf8.
Now we find some problem while working with the old data in our application which is java based.
We are getting the following error "java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv".
We further analyzed our data and found some interesting things :
e.g.
DB - UTF8.
NL_LANG also set to UTF8.
Select name from t1 where name like 'Gen%';
NAME
Genhve
But when we find out the length of the same data it show like this
NAME LENGTH(NAME) VSIZE(NAME)
Genhve 4 6
The question is why is it showing length as 4 only and when we try to use a substr function
its extracting like the following :-
select name,substr(name,4,1) from t1 where name like 'Gen%';
NAME SUB
Genhve hve
We have execute the above queries on US7ASCII DB and it is working fine, length it shows 6
and using SUBSTR it extracts just 'h' as well.
We also used dump function on the UTF8 Db for the above query,,this is the result :-
select name,length(name),vsize(name),dump(name) from t1 where name like 'Gen%';
NAME LENGTH(NAME) VSIZE(NAME) DUMP(NAME)
Genhve 4 6 Typ=1 Len=6: 71,101,110,232,118,101
We checked a lot with the data and it seems 'h' (accented e) is posing the problem.
We want to know where is the problem and how to overcome this.
Further, we tried all of the following :
1)
Export Server: US7ASCII
Export Client: did not set NLS_LANG / NLS_CHAR, so presumably US7ASCII as well
Import Client: did not set NLS_LANG / NLS_CHAR, so presumably US7ASCII as well
Import Server: UTF8
RESULT: Acute e became h
2)
Export Server: US7ASCII
Export Client: did not set NLS_LANG / NLS_CHAR, so presumably US7ASCII as well
Import Client: NLS_LANG=AMERICAN_AMERICA.UTF8 and NLS_CHAR=UTF8
Import Server: UTF8
RESULT: IMP 00016 error
3)
Export Server: US7ASCII
Export Client: NLS_LANG=AMERICAN_AMERICA.UTF8 and NLS_CHAR=UTF8
Import Client: did not set NLS_LANG / NLS_CHAR, so presumably US7ASCII as well
Import Server: UTF8
RESULT: Acute E became h
4)
Export Server: US7ASCII
Export Client: NLS_LANG=AMERICAN_AMERICA.UTF8 and NLS_CHAR=UTF8
Import Client: NLS_LANG=AMERICAN_AMERICA.UTF8 and NLS_CHAR=UTF8
Import Server: UTF8
RESULT: Acute e became h
5)
Tried using Update sys.props$
set value$='UTF8'
where name='NLS_CHARACTERSET'
RESULT: Acute e shows properly but it gives problem in the application
"java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv"
Looking further it was observed the following:
when you try this command on a column 'city' in a table which contains 'Genhva' (note the acute e after n), it shows
command: select length(city), vsize(city),substr(city,4,1),city from cities
Result: 4 6 hva Genhva
if you see the value of substr(city,4,1) , you will see the problem. Also note that the length shows 4 and size shows 6. Moreover, when these records are selected through JDBC Driver, it starts giving problems.
6)
Actually the above (point no. 5) is similar to changing the character set of the database with 'ALTER DATABASE CHARACTER SET UTF8'. Same problem is observed then too.
7)
We have also tried to with another method, that is by changing the third byte of the export file which specifies the character set, to the UTF8 code by editing the export file with a Hexdecimal editor. After import the same problem has been observed as defined in (5) and (6) above.
We have no more ideas how to migrate without corrupting the data. Of course we have known the records where these characters occur through the Oracle's cssacn utility but we do not want to manually rectify each and every record by replacing it with an ASCII character. Any other idea as to how this can be accomplised?
Thanx
AshokThe problem you have is that although your original database is defined as US7ASCII, the data it contains is more than is covered by this code page (as the reply on Sept 4 to the previous posting already said).
This has probably happened because the client was also defined as US7ASCII, and when the DB and client are defined as having the same character set no conversion (or checdking) takes place when data is passed between them. However if you are using a Windows client then it will in fact be using Windows code page 1252 (Latin-1) or similar, and this allows many more characters, including h (accented e). So a user can enter all these characters and store them in the database, and similarly read them from the database, because data transfer is transparent.
When you did ALTER DATABASE CHARACTER SET UTF8 this will only change the label on the database, but not affect the contents. However only part of the contents are valid UTF8, any character above 7F (like h) is invalid. If your original client now uses the database, code page transformation will take place because the client and DB have different character sets defined. The invalid codes can then cause problems.
Without being able to explain what has happened in detail, it may help to see what your h (dec 232, x'E8') looks like. The actual data has not changed (you can see this as it is reported as 232). However the binary code there (11101000) is invalid UTF8. UTF8 encodes a character in 1 to 4 bytes, and the first bits in a UTF8 character tell how many bytes it uses. 0xxx tell it is one byte (same as the corresponding USASCII character), 110x that it uses 2 bytes, 1110 that it uses 3 bytes etc. So if you interpret what is there as UTF8 it looks like the first byte of a 3-byte character, which explains why the substringing is giving you the other 2 bytes as well.
Can you fix this without losing data? I believe yes. First you should check what other characters are being flagged by the scan. See if these are contained in another standard character set. If they are only Western European accentet characters then WE8ISO8859P1 is probably ok, but watch out for the euro sign which Windows has at x'80', an undefined character in ISO8859-1.
You can see the contents of the Microsoft Windows Codepage 1252 at: http://www.microsoft.com/globaldev/reference/sbcs/1252.htm
For a listing of the US-ASCII defined characters see http://czyborra.com/charsets/iso646.html and for ISO 8859-1 see http://czyborra.com/charsets/iso8859.html#ISO-8859-1
If all is well, you can first ALTER DATABASE CHARACTER SET to WE8ISO8859P1. This will not change any data, but ensure that all the data gets exported. Then export the DB and import it to a UTF8 DB. This will convert the non-US-ASCII characters to Unicode. You will also have to change the clients character set to something other than USASCII or they will just see ? for the other characters.
Good Luck! -
Fail to convert between UTF8 and UCS2: failUTF8Conv
We need to store possibly all UTF8 chararacter in his database
especially $ & ( 4 8 < = > from WE8ISO8859P1 and from WE8ISO8859P15.
So we install an UTF8 instance and set NLS_LANG to UTF8.
We have to do select/update from a java client and sqlplus(like).
When we insert with java client it's unreadable from sqlplus and
when whe insert from sqlplus we've got 'Fail to convert between UTF8 and UCS2: failUTF8Conv '
here the code made in sqlplus
update CPW_TEST set lb_comportement='$ & ( 4 8 < = > ' WHERE ID_TEST=14805;
here the code made in java
update CPW_TEST set lb_comportement='$ & ( 4 8 < = > ' WHERE ID_TEST=14804;
and then the result in database
SELECT id_test,LB_COMPORTEMENT FROM CPW_TEST WHERE ID_TEST=14804 or ID_TEST=14805
ID_TEST LB_COMPORTEMENT
14804 B$ B& B( B4 B8 B< B= B> B
14805 $ & ( 4 8 < = >
2 rows selected
and the dump
SELECT id_test,dump(LB_COMPORTEMENT) FROM CPW_TEST WHERE ID_TEST=14804 or ID_TEST=14805
ID_TEST DUMP(LB_COMPORTEMENT)
14804 Typ=1 Len=26: 194,164,32,194,166,32,194,168,32,194,180,32,194,184,32,194,188,32,194,189,32,194,190,32,194,128
14805 Typ=1 Len=17: 164,32,166,32,168,32,180,32,184,32,188,32,189,32,190,32,128
2 rows selected
I'm not sure, but it seems that sqlplus uses true UTF8 (variable length codes) and java client uses UCS-2 (2 bytes)
How can I solve my problem?
Our configuration
javaclient (both thin and oci jdbc driver 8.1.7), sqlplus client and database Oracle 8.1.7.0.0 on the same computer (W2000 or NT4)
Thank you for yoru attention.Hi Luis, thanks for your suggestions. You're right that problem was in JServ and his JVM.
There was conflict between different versions of Java. While iFS was using JRE 1.3.1, JServ was configured to use JRE 1.1.8. As soon as I corrected link to the right Java, problem disappears.
Radek -
Problems with Accented Characters after migrating to UTF8
Hi,
I am puzzled about the following problem.
We have recently changed the database character set from US7ASCII to UTF8 for the internationalization
purpose. We ran the Character set scanner utility and it did report that some data may pose problems.
We followed the the below mentioned process to convert into UTF8 -
1) alter database character set utf8
2) alter database national character set utf8.
Now we find some problem while working with the old data in our application which is java based.
We are getting the following error "java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv".
We further analyzed our data and found some interesting things :
e.g.
DB - UTF8.
NL_LANG also set to UTF8.
Select name from t1 where name like 'Gen%';
NAME
Genhve
But when we find out the length of the same data it show like this
NAME LENGTH(NAME) VSIZE(NAME)
Genhve 4 6
My question is why is it showing length as 4 only and when we try to use a substr function
its extracting like the following :-
select name,substr(name,4,1) from t1 where name like 'Gen%';
NAME SUB
Genhve hve
We have execute the above queries on US7ASCII DB and it is working fine, length it shows 6
and using SUBSTR it extracts just 'h' as well.
I also used dump function on the UTF8 Db for the above query,,this is the result :-
select name,length(name),vsize(name),dump(name) from t1 where name like 'Gen%';
NAME LENGTH(NAME) VSIZE(NAME) DUMP(NAME)
Genhve 4 6 Typ=1 Len=6: 71,101,110,232,118,101
I checked a lot with the data and it seems 'h' (accented e) is posing the problem.
I want to know where is the problem and how to overcome this.
Regards
SibaWe ran the Character set scanner utility and it did report that some data may pose problems. Did you check out the documentation with the scanner ? It explains why and how to deal with problem data.
The problems are :-
1. You had invalid data inside your original US7ASCII database . h is not a valid 7 bit ASCII character. All the invalid US7ASCII characters, ( ie. all those that will be lost after doing ALTER DATABASE CHARACTER SET ) would have been flagged by the scanner.
2. All non 7 bit ASCII characters need to be converted to their UTF8 counterpart values, and typically these characters will have size expansions too. for example ,from 1 byte to 2 bytes.
3. ALTER DATABASE CHARACTER SET UTF8 changes the character set tag in the database header only. No data conversions are performed to your existing data .
Hi,
I am puzzled about the following problem.
We have recently changed the database character set from US7ASCII to UTF8 for the internationalization
purpose. We ran the Character set scanner utility and it did report that some data may pose problems.
We followed the the below mentioned process to convert into UTF8 -
1) alter database character set utf8
2) alter database national character set utf8.
Now we find some problem while working with the old data in our application which is java based.
We are getting the following error "java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv".
We further analyzed our data and found some interesting things :
e.g.
DB - UTF8.
NL_LANG also set to UTF8.
Select name from t1 where name like 'Gen%';
NAME
Genhve
But when we find out the length of the same data it show like this
NAME LENGTH(NAME) VSIZE(NAME)
Genhve 4 6
My question is why is it showing length as 4 only and when we try to use a substr function
its extracting like the following :-
select name,substr(name,4,1) from t1 where name like 'Gen%';
NAME SUB
Genhve hve
We have execute the above queries on US7ASCII DB and it is working fine, length it shows 6
and using SUBSTR it extracts just 'h' as well.
I also used dump function on the UTF8 Db for the above query,,this is the result :-
select name,length(name),vsize(name),dump(name) from t1 where name like 'Gen%';
NAME LENGTH(NAME) VSIZE(NAME) DUMP(NAME)
Genhve 4 6 Typ=1 Len=6: 71,101,110,232,118,101
I checked a lot with the data and it seems 'h' (accented e) is posing the problem.
I want to know where is the problem and how to overcome this.
Regards
Siba -
Java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
Hi all,
I am writing a servlet that connects to Oracle 8.0.6 through jdbc for jdk1.2 on NT 4.0
English version and it works fine.
But when the servlet is deployed to a solaris with Oracle 8.0.5 (not a typo, the oracle on
NT is 8.0.6 and oracle on solaris is 8.0.5) and jdbc for jdk1.2 (of course, for Solaris),
the servlet failed with the Exception:
java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
(I am using JRun 3.0 as the application and web server for both NT and Solaris)
(The database in both the NT and solaris platform are using UTF8 charset)
My servlet looks like this: (dbConn is a Connection object proved to be connected to Oracle
in previous segment of the same method):
String strSQL = "SELECT * FROM test";
try { Statement stmt = dbConn.createStatement();
ResultSet rs = stmt.execute(strSQL);
while (rs.next()) {
out.println("id = " + rs.getInt("id"));
System.out.println("id written");
out.println("name = " + rs.getString("name")); // <-- this is the line the
exception is thrown
System.out.println("name written");
} catch (java.sql.SQLException e) {
System.out.println("SQL Exception");
System.out.println(e);
The definition of the "test" table is:
create table test(
id number(10,0),
name varchar2(30));
There are about 10 rows exists in the table "test", in which all rows contains ONLY chinese
characters in the "name" field.
And when I view the System log, the string "id written" is shown EXACTLY ONCE and then there
is:
SQL Exception
java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
That means the resultset is fetch back from the database correctly. The problem arise only
during the getString("name") method.
Again, this problem only happens when the servlet is run on the solaris platform.
At first I would expect there are some strange code shown on the web page rather than having
an exception. I know that I should use getBytes to convert between different encodings, but
that's another story.
One more piece of information: When all the rows contains ascii characters in their "name"
field, the servlet works perfectly even in solaris.
If anyone knows why and how to tackle the problem please let me know. You can feel free to
send email to me at [email protected]
Many thanks,
Ben
nullHi all,
For the problem I previously posted, I found that Oracle had had such bug filed before in Oracle 7.3.2 (something like that) and is classified to be NOT A BUG.
A further research leads me to the document of Oracle that the error message:
"java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv"
is a JDBC driver error message of error number ORA-17037.
I'm still wondering why this behaviour will happen only in Solaris platform. The servlet on an NT machine I am using (which has an Oracle 8.0.6 and jdbc for jdk 1.2 running) is working just fine. I also suspect that this may be some sort of mistakes from jdbc driver.
Nevertheless, I have found a way to work around the problem that I cannot get non-English string from Oracle in Solaris and I would like to share it with you all here.
Before I go on, I found that there are many people out there on the web that encounter the same problem. (Some of which said s/he has been working on this problem for a month). As a result, if you find this way of working around the problem does help you, please tell those who have the same problem but don't know how to tackle. Thanks very much.
Here's the way I work it out. It's kinda simple, but it does work:
Instead of using:
String abc = rs.getString("SomeColumnContainsNonEnglishCharacters");
I used this:
String abc = new String(rs.getBytes("SomeColumnContainsNonEnglishCharacters"));
This will give you a string WITH YOUR DEFAULT CHARSET (or ENCODING) from your system.
If you want to convert the string read to some other encoding type, say Big5, you can do it like this:
String abc = new String(rs.getBytes("SomeColumneContainsNonEnglishCharacters"), "BIG5");
Again, it's simple, but it works.
Finally, if anyone knows why the fail to convert problem happens, please kindly let me know by leaving a word in [email protected]
Again, thanks to those of you who had tried to help me out.
Creambun
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by creambun creambun ([email protected]):
Hi all,
I am writing a servlet that connects to Oracle 8.0.6 through jdbc for jdk1.2 on NT 4.0
English version and it works fine.
But when the servlet is deployed to a solaris with Oracle 8.0.5 (not a typo, the oracle on
NT is 8.0.6 and oracle on solaris is 8.0.5) and jdbc for jdk1.2 (of course, for Solaris),
the servlet failed with the Exception:
java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
(I am using JRun 3.0 as the application and web server for both NT and Solaris)
(The database in both the NT and solaris platform are using UTF8 charset)
My servlet looks like this: (dbConn is a Connection object proved to be connected to Oracle
in previous segment of the same method):
String strSQL = "SELECT * FROM test";
try { Statement stmt = dbConn.createStatement();
ResultSet rs = stmt.execute(strSQL);
while (rs.next()) {
out.println("id = " + rs.getInt("id"));
System.out.println("id written");
out.println("name = " + rs.getString("name")); // <-- this is the line the
exception is thrown
System.out.println("name written");
} catch (java.sql.SQLException e) {
System.out.println("SQL Exception");
System.out.println(e);
The definition of the "test" table is:
create table test(
id number(10,0),
name varchar2(30));
There are about 10 rows exists in the table "test", in which all rows contains ONLY chinese
characters in the "name" field.
And when I view the System log, the string "id written" is shown EXACTLY ONCE and then there
is:
SQL Exception
java.sql.SQLException: Fail to convert between UTF8 and UCS2: failUTF8Conv
That means the resultset is fetch back from the database correctly. The problem arise only
during the getString("name") method.
Again, this problem only happens when the servlet is run on the solaris platform.
At first I would expect there are some strange code shown on the web page rather than having
an exception. I know that I should use getBytes to convert between different encodings, but
that's another story.
One more piece of information: When all the rows contains ascii characters in their "name"
field, the servlet works perfectly even in solaris.
If anyone knows why and how to tackle the problem please let me know. You can feel free to
send email to me at [email protected]
Many thanks,
Ben<HR></BLOCKQUOTE>
null -
I update from Jdeveloper31 to Jdeveloper3112 ,my program is wrong,but it is good in Jdeveloper31 .
problem :
LoadFromResultSet failed (2)
JBO-27022: Failed to load value at index 2 with java object of type java.lang.String due to java.sql.SQLException.
void oracle.dacf.dataset.DataItemImpl.fireItemsAvailable(javax.infobus.InfoBus, java.lang.String, javax.infobus.InfoBusDataProducer, boolean)
void oracle.dacf.dataset.DataItemImpl.fireItemsAvailable(javax.infobus.InfoBus, java.lang.String, javax.infobus.InfoBusDataProducer, boolean)
void oracle.dacf.dataset.DataItemImpl.publish(boolean)
void oracle.dacf.dataset.ProducerObject.publishDataItem(boolean)
void oracle.dacf.dataset.SessionInfo.publishSession(boolean)
void oracle.dacf.dataset.SessionInfo.publishSession()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderPanel.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderFrame.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderApp.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderApp.main(java.lang.String[])
java.sql.SQLException: failUTF8Conv
void oracle.dacf.dataset.DataItemImpl.fireItemsAvailable(javax.infobus.InfoBus, java.lang.String, javax.infobus.InfoBusDataProducer, boolean)
void oracle.dacf.dataset.DataItemImpl.fireItemsAvailable(javax.infobus.InfoBus, java.lang.String, javax.infobus.InfoBusDataProducer, boolean)
void oracle.dacf.dataset.DataItemImpl.publish(boolean)
void oracle.dacf.dataset.ProducerObject.publishDataItem(boolean)
void oracle.dacf.dataset.SessionInfo.publishSession(boolean)
void oracle.dacf.dataset.SessionInfo.publishSession()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderPanel.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderFrame.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderApp.<init>()
void KJ.Fareview.App.Admin.WorkOrder.WorkOrderApp.main(java.lang.String[])
nullHi, Beverley.
Thank you for visiting Apple Support Communities.
I understand that you are unable to trim clips using iMovie. I would need a little more information on how you were attempting to trim a clip to provide a better answer. However, make sure you have the movie project open and are selecting the clip that you wish to trim as this will activate the clip trimmer.
Trim clips
-Jason H. -
I am trying to implement some kind of a server listening for requests. The listener part of the app, is a daemon thread that listens for connections and instantiates a handling daemon thread once it gets some. However, my problem is that i must be able to kill the listening thread at the user's will (say via a sto button). I have done this via the Sun's proposed way, by testing a boolean flag in the loop, which is set to false when i wish to kill the thread. The problem with this thing is the following...
Once the thread starts excecuting, it will test the flag, find it true and enter the loop. At some point it will LOCK on the server socket waiting for connection. Unless some client actually connects, it will keep on listening indefinatelly whithought ever bothering to check for the flag again (no matter how many times you set the damn thing to false).
My question is this: Is there any real, non-theoretical, applied way to stop thread in java safely?
Thank you in advance,
LeftyThis was one solution from the socket programming forum, have you tried this??
public Thread MyThread extends Thread{
boolean active = true;
public void run(){
ss.setSoTimeout(90);
while (active){
try{
serverSocket = ss.accept();
catch (SocketTimeoutException ste){
// do nothing
// interrupt thread
public void deactivate(){
active = false;
// you gotta sleep for a time longer than the
// accept() timeout to make sure that timeout is finished.
try{
sleep(91);
}catch (InterruptedException ie){
interrupt();
} -
A problem with Threads and MMapi
I am tring to execute a class based on Game canvas.
The problem begin when I try to Play both a MIDI tone and to run an infinit Thread loop.
The MIDI tone "Stammers".
How to over come the problem?
Thanks in advance
Kobi
See Code example below:
import java.io.IOException;
import java.io.InputStream;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
public class MainScreenCanvas extends GameCanvas implements Runnable {
private MainMIDlet parent;
private boolean mTrucking = false;
Image imgBackgound = null;
int imgBackgoundX = 0, imgBackgoundY = 0;
Player player;
public MainScreenCanvas(MainMIDlet parent)
super(true);
this.parent = parent;
try
imgBackgound = Image.createImage("/images/area03_bkg0.png");
imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
imgBackgoundY = this.getHeight() - imgBackgound.getHeight();
catch(Exception e)
System.out.println(e.getMessage());
* starts thread
public void start()
mTrucking = true;
Thread t = new Thread(this);
t.start();
* stops thread
public void stop()
mTrucking = false;
public void play()
try
InputStream is = getClass().getResourceAsStream("/sounds/scale.mid");
player = Manager.createPlayer(is, "audio/midi");
player.setLoopCount(-1);
player.prefetch();
player.start();
catch(Exception e)
System.out.println(e.getMessage());
public void run()
Graphics g = getGraphics();
play();
while (true)
tick();
input();
render(g);
* responsible for object movements
private void tick()
* response to key input
private void input()
int keyStates = getKeyStates();
if ((keyStates & LEFT_PRESSED) != 0)
imgBackgoundX++;
if (imgBackgoundX > 0)
imgBackgoundX = 0;
if ((keyStates & RIGHT_PRESSED) != 0)
imgBackgoundX--;
if (imgBackgoundX < this.getWidth() - imgBackgound.getWidth())
imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
* Responsible for the drawing
* @param g
private void render(Graphics g)
g.drawImage(imgBackgound, imgBackgoundX, imgBackgoundY, Graphics.TOP | Graphics.LEFT);
this.flushGraphics();
}You can also try to provide a greater Priority to your player thread so that it gains the CPU time when ever it needs it and don't harm the playback.
However a loop in a Thread and that to an infinite loop is one kind of very bad programming, 'cuz the loop eats up most of your CPU time which in turn adds up more delays of the execution of other tasks (just as in your case it is the playback). By witting codes bit efficiently and planning out the architectural execution flow of the app before start writing the code helps solve these kind of issues.
You can go through [this simple tutorial|http://oreilly.com/catalog/expjava/excerpt/index.html] about Basics of Java and Threads to know more about threads.
Regds,
SD
N.B. And yes there are more articles and tutorials available but much of them targets the Java SE / EE, but if you want to read them here is [another great one straight from SUN|http://java.sun.com/docs/books/tutorial/essential/concurrency/index.html] .
Edited by: find_suvro@SDN on 7 Nov, 2008 12:00 PM -
Hi all,
I would like to ask you for a help. I need to write a small program at my university. I started to write a midlet which function would be to countdown time for sports activities. I woul like to start a new thread - the one that counts down - and at the same time make the main thread sleep. After the "countdown" thread finishes, the main thread wakes up and waits for user input. The problem is that when the "countdown" thread finishes his work, I've got Uncaught exception java/lang/NullPointerException. error and the midlet halts.
Below you can find the code
import java.lang.*;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class intervals extends MIDlet implements CommandListener
public Display ekran;
private SweepCanvas sweeper;
private Form rundy;
private TextField round0, round1, round2, round3, round4, round5, round6, round7, round8;
private long czas,x;
private Command exitCommand;
private Command addRound;
private Command delRound;
private Command start;
private TextField repeat;
private Form odliczanie;
private Alert ostrz;
Licznik thread;
String test;
StringItem test1;
int parz,i,j,k;
static int l;
int ilrund;
int ilpowt;
Item sec;
long sec1;
public intervals()
rundy = new Form("Interwały sportowe");
exitCommand = new Command("Wyjście", Command.EXIT, 2);
addRound = new Command("Dodaj","Dodaj rundę", Command.ITEM,1);
delRound = new Command("Usuń","Usuń ostatnią rundę", Command.ITEM,1);
start = new Command("Start", Command.ITEM,1);
odliczanie = new Form("Odliczanie");
TextField dodaj(TextField kolej)
kolej=new TextField("Podaj czas (s) rundy "+parz,null, 4, TextField.NUMERIC);//stworzenie nowej instancji do wybierania czasu trwania rundy
if(rundy.size()==0)
rundy.insert(rundy.size(),kolej);
else
rundy.insert(rundy.size()-1, kolej);
return kolej;
void odliczanie(TextField round)
monitor m=new monitor();
k=Integer.parseInt(round.getString());
ekran.setCurrent(odliczanie);
thread=new Licznik(k,odliczanie);
thread.start();
ekran.setCurrent(rundy);
public void startApp()// throws MIDletStateChangeException
rundy.deleteAll();
repeat = new TextField("Podaj ilość powtórzeń",null,1,TextField.NUMERIC);
rundy.addCommand(addRound);
rundy.addCommand(exitCommand);
rundy.setCommandListener(this);
Canvas obrazek = new MyCanvas();
ekran = Display.getDisplay(this);
ekran.setCurrent(obrazek);
czas=System.currentTimeMillis();
while (System.currentTimeMillis()<czas+1000)
continue;
ekran.setCurrent(rundy);
public void pauseApp()
public void destroyApp(boolean unconditional)
notifyDestroyed();
public void commandAction(Command c, Displayable s)
if (c == exitCommand)
destroyApp(false);
notifyDestroyed();
else if(c==addRound)
if(rundy.size()==0)//Sprawdzenie ilości elementów w celu poprawnego wyświetlania liczby rund w formie
parz=1;
else
parz=rundy.size();
switch(parz)
case 1:
round0=dodaj(round0);break;
case 2:
round1=dodaj(round1);break;
case 3:
round2= dodaj(round2);break;
case 4:
round3=dodaj(round3);break;
case 5:
round4=dodaj(round4);break;
default:
ostrz=new Alert("Uwaga","Maksymalna liczba rund wynosi 9", null, AlertType.INFO);
ostrz.setTimeout(3000);
ekran.setCurrent(ostrz);
if(rundy.size()==1)
rundy.append(repeat);
rundy.addCommand(start);
rundy.addCommand(delRound);
else if(c==delRound)
if(rundy.size()!=0)
rundy.delete(rundy.size()-2);
if (rundy.size()==1)
rundy.deleteAll();
if(rundy.size()==0)
rundy.removeCommand(delRound);
rundy.removeCommand(start);
else if(c==start)
ilrund=rundy.size()-1;
if(this.repeat.size()>0)
ilpowt=Integer.parseInt(this.repeat.getString());
ekran = Display.getDisplay(this);
for (i=1; i<=ilpowt;i++)
odliczanie= new Form("Odliczanie");
for (j=0;j<ilrund;j++)
switch(j)
case 0:
odliczanie(round0);
break;
case 1:
odliczanie(round1);
break;
case 2:
odliczanie(round2);
break;
case 3:
odliczanie(round3);
break;
case 4:
odliczanie(round4);
break;
case 5:
odliczanie(round5);
break;
case 6:
odliczanie(round6);
break;
case 7:
odliczanie(round7);
break;
case 8:
odliczanie(round8);
break;
class Licznik extends Thread
int czas1,k;
Form forma;
monitor m;
public Licznik(int k,Form formap)
czas1=k;
forma=formap;
public synchronized void run()
while(czas1>0)
forma.deleteAll();
forma.append("Czas pozostały (s): "+czas1);
try{Thread.sleep(1000);} catch(InterruptedException e){e.printStackTrace();}
czas1--;
if(czas1<=0)
m.put();
}and monitor class
public class monitor
boolean busy=false;
synchronized void get()
if(!busy)
try
wait();
}catch(InterruptedException e){e.printStackTrace();}
notify();
synchronized void put()
if(busy)
try
wait();
}catch(InterruptedException e){e.printStackTrace();}
busy=true;
notify();
}Can anybody help me with this?Groovemaker,
Your Licznik class has a member m of type monitor, which has not been instantiated (in other words is null) hence, when calling m.put() you get NullPointerException. Please also mind, that using Thread.sleep(1000) is not an accurate way of measuring time.
If I may, please use recommended for Java class naming conventions - some of your names use lower case, while other don't which is confusing to the reader.
Daniel -
Problem with threads within applet
Hello,
I got an applet, inside this applet I have a singleton, inside this singleton I have a thread.
this thread is running in endless loop.
he is doing something and go to sleep on and on.
the problem is,
when I refresh my IE6 browser I see more than 1 thread.
for debug matter, I did the following things:
inside the thread, sysout every time he goes to sleep.
sysout in the singleton constructor.
sysout in the singleton destructor.
the output goes like this:
when refresh the page, the singleton constructor loading but not every refresh, sometimes I see the constructor output and sometimes I dont.
The thread inside the singleton is giving me the same output, sometime I see more than one thread at a time and sometimes I dont.
The destructor never works (no output there).
I don't understand what is going on.
someone can please shed some light?
thanks.
btw. I am working with JRE 1.1
this is very old and big applet and I can't convert it to something new.Ooops. sorry!
I did.
public void start() {
public void stop() {
public void destroy() {
try {
resetAll();
Configuration.closeConnection();
QuoteItem.closeConnection();
} finally {
try {
super.finalize();
} catch (Throwable e) {
e.printStackTrace();
} -
Problem with Threads and a static variable
I have a problem with the code below. I am yet to make sure that I understand the problem. Correct me if I am wrong please.
Code functionality:
A timer calls SetState every second. It sets the state and sets boolean variable "changed" to true. Then notifies a main process thread to check if the state changed to send a message.
The problem as far I understand is:
Assume the timer Thread calls SetState twice before the main process Thread runs. As a result, "changed" is set to true twice. However, since the main process is blocked twice during the two calls to SetState, when it runs it would have the two SetState timer threads blocked on its synchronized body. It will pass the first one, send the message and set "changed" to false since it was true. Now, it will pass the second thread, but here is the problem, "changed" is already set to false. As a result, it won't send the message even though it is supposed to.
Would you please let me know if my understanding is correct? If so, what would you propose to resolve the problem? Should I call wait some other or should I notify in a different way?
Thanks,
B.D.
Code:
private static volatile boolean bChanged = false;
private static Thread objMainProcess;
protected static void Init(){
objMainProcess = new Thread() {
public void run() {
while( objMainProcess == Thread.currentThread() ) {
GetState();
objMainProcess.setDaemon( true );
objMainProcess.start();
public static void initStatusTimer(){
if(objTimer == null)
objTimer = new javax.swing.Timer( 1000, new java.awt.event.ActionListener(){
public void actionPerformed( java.awt.event.ActionEvent evt){
SetState();
private static void SetState(){
if( objMainProcess == null ) return;
synchronized( objMainProcess ) {
bChanged = true;
try{
objMainProcess.notify();
}catch( IllegalMonitorStateException e ) {}
private static boolean GetState() {
if( objMainProcess == null ) return false;
synchronized( objMainProcess ) {
if( bChanged) {
SendMessage();
bChanged = false;
return true;
try {
objMainProcess.wait();
}catch( InterruptedException e ) {}
return false;
}Thanks DrClap for your reply. Everything you said is right. It is not easy to make them alternate since SetState() could be called from different places where the state could be anything else but a status message. Like a GREETING message for example. It is a handshaking message but not a status message.
Again as you said, There is a reason I can't call sendMessage() inside setState().
The only way I was able to do it is by having a counter of the number of notifies that have been called. Every time notify() is called a counter is incremented. Now instead of just checking if "changed" flag is true, I also check if notify counter is greater than zero. If both true, I send the message. If "changed" flag is false, I check again if the notify counter is greater than zero, I send the message. This way it works, but it is kind of a patch than a good design fix. I am yet to find a good solution.
Thanks,
B.D. -
Problem with threads running javaw
Hi,
Having a problem with multi thread programming using client server sockets. The program works find when starting the the application in a console using java muti.java , but when using javaw multi.java the program doesnt die and have to kill it in the task manager. The program doesnt display any of my gui error messages either when the server disconnect the client. all works find in a console. any advice on this as I havent been able to understand why this is happening? any comment would be appreciated.
troy.troy,
Try and post a minimum code sample of your app which
does not work.
When using javaw, make sure you redirect the standard
error and standard output streams to file.
Graeme.Hi Graeme,
I dont understand what you mean by redirection to file? some of my code below.
The code works fine under a console, code is supposed to exit when the client (the other server )disconnects. the problem is that but the clientworker side of the code still works. which under console it doesnt.
public class Server{
ServerSocket aServerSocket;
Socket dianosticsSocket;
Socket nPortExpress;
ClientListener aClientListener;
LinkedList queue = new LinkedList();
int port = 0;
int clientPort = 0;
String clientName = null;
boolean serverAlive = true;
* Server constructor generates a server
* Socket and then starts a client threads.
* @param aPort socket port of local machine.
public Server(int aPort, String aClientName, int aClientPort){
port = aPort;
clientName = aClientName;
clientPort = aClientPort;
try{
// create a new thread
aServerSocket = new ServerSocket(port) ;
// connect to the nPortExpress
aClientListener = new ClientListener(InetAddress.getByName(clientName), clientPort, queue,this);
// aClientListener.setDaemon(true);
aClientListener.start();
// start a dianostic port
DiagnosticsServer aDiagnosticsServer = new DiagnosticsServer(port,queue,aClientListener);
// System.out.println("Server is running on port " + port + "...");
// System.out.println("Connect to nPort");
catch(Exception e)
// System.out.println("ERROR: Server port " + port + " not available");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Server port " + port + " not available", JOptionPane.ERROR_MESSAGE);
serverAlive = false;
System.exit(1);
while(serverAlive&&aClientListener.hostSocket.isConnected()){
try{
// connect the client
Socket aClient = aServerSocket.accept();
//System.out.println("open client connection");
//System.out.println("client local: "+ aClient.getLocalAddress().toString());
// System.out.println("client localport: "+ aClient.getLocalPort());
// System.out.println("client : "+ aClient.getInetAddress().toString());
// System.out.println("client port: "+ aClient.getLocalPort());
// make a new client thread
ClientWorker clientThread = new ClientWorker(aClient, queue, aClientListener, false);
// start thread
clientThread.start();
catch(Exception e)
//System.out.println("ERROR: Client connection failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client connection failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end constructor Server
void serverExit(){
JOptionPane.showMessageDialog(null, "Server ","ERROR: nPort Failure", JOptionPane.ERROR_MESSAGE);
System.exit(1);
}// end class Server
*** connect to another server
public class ClientListener extends Thread{
InetAddress hostName;
int hostPort;
Socket hostSocket;
BufferedReader in;
PrintWriter out;
boolean loggedIn;
LinkedList queue; // reference to Server queue
Server serverRef; // reference to main server
* ClientListener connects to the host server.
* @param aHostName is the name of the host eg server name or IP address.
* @param aHostPort is a port number of the host.
* @param aLoginName is the users login name.
public ClientListener(InetAddress aHostName, int aHostPort,LinkedList aQueue,Server aServer) // reference to Server queue)
hostName = aHostName;
hostPort = aHostPort;
queue = aQueue;
serverRef = aServer;
// connect to the server
try{
hostSocket = new Socket(hostName, hostPort);
catch(IOException e){
//System.out.println("ERROR: Connection Host Failed");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort Failed", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end constructor ClientListener
** multi client connection server
ClientWorker(Socket aSocket,LinkedList aQueue, ClientListener aClientListener, boolean diagnostics){
queue = aQueue;
addToQueue(this);
client = aSocket;
clientRef = aClientListener;
aDiagnostic = diagnostics;
} // end constructor ClientWorker
* run method is the main loop of the server program
* in change of handle new client connection as well
* as handle all messages and errors.
public void run(){
boolean alive = true;
String aSubString = "";
in = null;
out = null;
loginName = "";
loggedIn = false;
while (alive && client.isConnected()&& clientRef.hostSocket.isConnected()){
try{
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
if(aDiagnostic){
out.println("WELCOME to diagnostics");
broadCastDia("Connect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
out.println("WELCOME to Troy's Server");
broadCastDia("Connect : client "+client.getInetAddress().toString());
out.flush();
String line;
while(((line = in.readLine())!= null)){
StringTokenizer aStringToken = new StringTokenizer(line, " ");
if(!aDiagnostic){
broadCastDia(line);
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
else{
if(line.equals("GETIPS"))
getIPs();
else{
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
} // end while
catch(Exception e){
// System.out.println("ERROR:Client Connection reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR:Client Connection reset", JOptionPane.ERROR_MESSAGE);
try{
if(aDiagnostic){
broadCastDia("Disconnect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
broadCastDia("Disconnect : client "+client.getInetAddress().toString());
out.flush();
// close the buffers and connection;
in.close();
out.close();
client.close();
// System.out.println("out");
// remove from list
removeThreadQueue(this);
alive = false;
catch(Exception e){
// System.out.println("ERROR: Client Connection reset failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client Connection reset failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end method run
* method run - Generates io stream for communicating with the server and
* starts the client gui. Run also parses the input commands from the server.
public void run(){
boolean alive = true;
try{
// begin to life the gui
// aGuiClient = new ClientGui(hostName.getHostName(), hostPort, loginName, this);
// aGuiClient.show();
in = new BufferedReader(new InputStreamReader(hostSocket.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(hostSocket.getOutputStream()));
while (alive && hostSocket.isConnected()){
String line;
while(((line = in.readLine())!= null)){
System.out.println(line);
broadCast(line);
} // end while
} // end while
catch(Exception e){
// System.out.println("ERRORa Connection to host reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort reset", JOptionPane.ERROR_MESSAGE);
try{
hostSocket.close();
}catch(Exception a){
JOptionPane.showMessageDialog(null, (a.toString()),"ERROR: Exception", JOptionPane.ERROR_MESSAGE);
alive = false;
System.exit(1);
} // end method run -
Problem with Threads and "plase wait..."-Window
Hi everyone,
I have a problem that I'm not able to solve in any way... I have a time-consuming task (a file decryption) which I execute in a separate thread; I've used the SwingWorker class, like suggested by sun-tutorial, and it works right. The problem is that I have to wait that the decryption have finished before continuing with program-execution. Therefore I would like to display a "please wait"-window while the task runs. I've tryed all the possible ways I know but the problem is always the same: the waitWindow is displayed empty, the bounds are painted but the contents no; it's only painted when the decrypt-task has finished. Please help me, I have no more resources....
decrypt-file code:
public class DecryptFile {
private String cryptedFileNameAndPath;
private ByteArrayInputStream resultStream = null;
// need for progress
private int lengthOfTask;
private int current = -1;
private String statMessage;
public DecryptFile(String encZipFileNameAndPath) {
cryptedFileNameAndPath = encZipFileNameAndPath;
//Compute length of task...
// 0 for indeterminate
lengthOfTask = 0;
public ByteArrayInputStream getDecryptedInputStream() {
return this.resultStream;
* Called from ProgressBarDemo to start the task.
public void go() {
current = -1;
final SwingWorker worker = new SwingWorker() {
public Object construct() {
return new ActualTask();
worker.start();
* Called from ProgressBarDemo to find out how much work needs
* to be done.
public int getLengthOfTask() {
return lengthOfTask;
* Called from ProgressBarDemo to find out how much has been done.
public int getCurrent() {
return current;
public void stop() {
current = lengthOfTask;
* Called from ProgressBarDemo to find out if the task has completed.
public boolean done() {
if (current >= lengthOfTask)
return true;
else
return false;
public String getMessage() {
return statMessage;
* The actual long running task. This runs in a SwingWorker thread.
class ActualTask {
ActualTask () {
current = -1;
statMessage = "";
resultStream = AIUtil.getInputStreamFromEncZip(cryptedFileNameAndPath); //here the decryption happens
current = 0;
statMessage = "";
}The code that calls decryption and displays waitWindow
final WaitSplash wS = new WaitSplash("Please wait...");
final DecryptFile cryptedTemplate = new DecryptFile (this.templateFile);
cryptedTemplate.go();
while (! cryptedTemplate.done()) {
try {
wait();
} catch (Exception e) { }
this.templateInputStream = cryptedTemplate.getDecryptedInputStream();
wS.close();Thanks, thanks, thanks in advance!
EdoardoMaybe you can try setting the priority of the long-running thread to be lower? so that the UI will be more responsive...
-
im using jdk 1.6 with java wtk 2.1
ya i know..
2.1 is a jdk1.4 source
but im using souce as 1.4 during compiliation so thats not the prob
this is my code
package org.learn;
import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.Display;
public class thtest extends MIDlet
Thread t;
public void startApp()
Alert a=new Alert("hello");
a.setString("hello");
Alert b=new Alert("world");
b.setString("world");
Display d = Display.getDisplay(this );
d.setCurrent(a);
t=Thread.currentThread();
try{
t.sleep(10000);
catch (Exception e){}
d.setCurrent(b);
public void pauseApp()
public void destroyApp(boolean unconditional)
its just supposed to pause between the alerts using threads
however when i run it using the wtk, the emulator run properly but when i launch the app, it stops executing giving me this:
"Error verifying method org/learn/thtest startApp()V
Approximate bytecode offset 49: Inconsistent or missing stackmap at target
%the stack info%
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
ALERT: java/lang/VerifyError: org/learn/thtest.
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
please can someone help me out with this, is it an error on my part or do i have to set some option.Hi gandalf123,
First, Thread.sleep is a static method, so you don't need to create a Thread object to use it.
I think the problem is due to the fact you don't preverify your midlet.
More over, you don't need to double post your question. -
Problem with threads and camera.
Hi everybody!
I've a problem with taking snapshot.
I would like to display a loading screen after it take snapshot ( sometimes i
have to wait few seconds after i took snapshot. Propably photo is being taken in time where i have to wait).
I was trying to use threads but i didn't succeed.
I made this code:
display.setCurrent(perform);
new Thread(new Runnable(){
public void run() {
while((!performing.isShown()) && (backgroundCamera.isShown())){
Thread.yield();
notifyAll();
}).start();
new Thread(new Runnable(){
public void run() {
try {
this.wait();
} catch(Exception e) {
exceptionHandler(e);
photo = camera.snapshot();
display.setCurrent(displayPhoto);
}).start();This code is sometimes showing performing screen but sometimes no.
I don't know why. In my opinion performing.isShown() method isn't working correctly.
Does anyone have some idea how to use threads here?Hi,
I've finally managed to work this fine.
The code:
Object o = new Object();
display.setCurrent(perform);
new Thread(new Runnable(){
public void run() {
while(!performing.isShown()){
Thread.yield();
synchronized(o) {
o.notify();
}).start();
new Thread(new Runnable(){
public void run() {
try {
synchronized(o) {
o.wait(1);
} catch(Exception e) {
exceptionHandler(e);
photo = camera.snapshot();
display.setCurrent(displayPhoto);
}).start();
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