How to Detect Database Conneciton Lost in Applet

Hi,
Is there a way to detect loss of database conneciton or network conneciton in an applet while it is running? We have an applet application and want to perform some database updates based on loss of database or network connectivity while the applet is running.
Just thinking out loud - is there a way to use some thread that constants runs in the loaded applet code and checks for database or network connectivity.
Thanks

That will be a manual process since we will know the list of users who had logged in thru the logs. What we are trying to do is to limit the concurrent connections for the users to the system. So if a conneciton is lost the users current count has to be decremented.
The select query you mentioned is trivial but how can we make this run all the time in the background. Do we use some thread etc?

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Hi,
I am trying to prepare database connection in applet. After preparing connection with database it'll read same values from table.
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I want to detect when the browser or Applet have been killed so that i can save the Annotation objects into XML format.
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ANSWER: HOW TO DETECT Java Plugin from JavaScript

I created a new topic because the questions about
how to detect Java Plugin in browsers are scattered
thoughout this forum.
Basically you need to employ two approaches for IE and NS.
In IE you need to try to instantiate a small applet
(not your production applet) in order to see if browser
can do it. if the browser can do it, you can make a
call applet from JavaScript in order to find version of
JRE (as well as a host of other things).
In NS you can write a simple JavaScript which will
interrogate the browser for all plugins installed. Then
ypu can make a desicion whether to pass execution to
the next(or generated) page which hosts your applet,
or ask the user to download/install a plugin.
I ecourage everybody to host a plugin on your site
rather leave default link to it which is generated by
html converter.
In order to run sample,
Prerequisites:
Java Plugin 1.3.
If you have a different version of plugin,
substitute hardcoded plugin version in JavaScript for
value that you have.
1. compile java file
2. put class file in the same directory with html file
3. load html file into the browser.
4. press "Check Java Plugin.." button
5. see it work
6. examine code
7. uninstall plugin
8. repeat steps 1 - 4
9. see it work
10. install plugin.
Sample code follows:
**********************HTML FILE BEGIN***********
<HTML>
<HEAD>

<TITLE>Detect Java Runtime</TITLE>
</HEAD>
<SCRIPT LANGUAGE="JavaScript">
var browsername;
function doNetscape()
for (i=0; i < navigator.plugins.length; i++)
for (j = 0; j < navigator.plugins.length; j++)
if(navigator.plugins[i][j].type == "application/x-java-applet;version=1.3")
alert("You are running Netscape with Java Plugin 1.3.0 - OK");
return;
alert("You are running Netscape\nPlease, install Java Runtime Environment 1.3.0");
function doMicrosoft()
var applet = document.myApplet;
if(applet == null)
alert("You are running Microsoft Browser.\nPlease, install Java Runtime Environment 1.3.0");
return;
var version = applet.getJavaVersion();
if(version == "1.3.0")
alert("You are running IE, Java Plugin 1.3.0 installed - OK");
else
alert("You are running IE, other plugin installed - mybe OK if later that 1.3.0\nYour version: " + version);
function getJava()
var applet = document.myApplet;
if(applet == null)
alert("Please, install Java Runtime Environment");
return;
     alert("JRE Version: " + document.myApplet.getJavaVersion());
function checkJavaPlugin()
     browsername = navigator.appName;
     if(browsername.indexOf("Netscape")!= -1)
          browsername="NS";
          doNetscape();
     else
          if(browsername.indexOf("Microsoft")!=-1)
               browsername="MSIE";
               doMicrosoft();
          else
               browsername="N/A";
               alert("Unknown browser: " + browsername);
</SCRIPT>
<body>
<Strong>Check Java Plugin</strong>
<OBJECT id="myApplet" classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
     WIDTH = 1
     HEIGHT = 1 >
     <PARAM NAME = CODE VALUE = "DetectPluginApplet.class" >
     <PARAM NAME="scriptable" VALUE="true" >
     <embed type="application/x-java-applet;version=1.3"
          code = DetectPluginApplet width = 2 height = 2 MAYSCRIPT = "true" >
     </embed>
     </EMBED>
</object>
<FORM>
     <INPUT TYPE="button" value="Get Plugin Version in IE" onClick="getJava()">
     <INPUT TYPE="button" value="Check Java Plugin in NS and IE" onClick="javascript:checkJavaPlugin()">
</FORM>
</BODY>
</HTML>
**********************HTML FILE END***********
***************APPLET FILE BEGIN***********
import java.awt.*;
public class DetectPluginApplet extends java.applet.Applet
     public void init()
          add(new Label("DetectPluginApplet"));
public String getJavaVersion()
return System.getProperty("java.version");
**************APPLLET FILE END************

Try following java script, it works on new browsers (NS 4+, IE5+). For IE you have to enable 'ActiveX objects creation' in security options.
var agt=navigator.userAgent.toLowerCase();
var is_major = parseInt(navigator.appVersion);
var is_nav = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
&& (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
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var is_ie = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
var is_ie5 = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );
var is_ie5_5 = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.5") !=-1));
var is_ie6 = (is_ie && (is_major == 4) && (agt.indexOf("msie 6.0") !=-1));
var is_ie5up = (is_ie && (is_major == 4)
&& ( (agt.indexOf("msie 5.0")!=-1)
|| (agt.indexOf("msie 5.5")!=-1)
|| (agt.indexOf("msie 6.0")!=-1) ) );
var pluginDetected = false;
var activeXDisabled = false;
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if(is_nav4up) {
// Refresh 'navigator.plugins' to get newly installed plugins.
// Use 'navigator.plugins.refresh(false)' to refresh plugins
// without refreshing open documents (browser windows)
if(navigator.plugins) {
navigator.plugins.refresh(false);
// check for Java plugin in installed plugins
if(navigator.mimeTypes) {
for (i=0; i < navigator.mimeTypes.length; i++) {
if( (navigator.mimeTypes[ i].type != null)
&& (navigator.mimeTypes[ i].type.indexOf(
"application/x-java-applet;jpi-version=1.3") != -1) ) {
pluginDetected = true;
break;
} else if (is_ie5up) {
var javaVersion;
var shell;
try {
// Create WSH(WindowsScriptHost) shell, available on Windows only
shell = new ActiveXObject("WScript.Shell");
if (shell != null) {
// Read JRE version from Window Registry
try {
javaVersion = shell.regRead("HKEY_LOCAL_MACHINE\\Software\\JavaSoft\\Java Runtime Environment\\CurrentVersion");
} catch(e) {
// handle exceptions raised by 'shell.regRead(...)' here
// so that the outer try-catch block would receive only
// exceptions raised by 'shell = new ActiveXObject(...)'
} catch(e) {
// Creating ActiveX controls thru script is disabled
// in InternetExplorer security options
// To enable it:
// a. Go to the 'Tools --> Internet Options' menu
// b. Select the 'Security' tab
// c. Select zone (Internet/Intranet)
// d. Click the 'Custom Level..' button which will display the
// 'Security Settings' window.
// e. Enable the option 'Initialize and script ActiveX controls
// not marked as safe'
activeXDisabled = true;
// Check whether we got required (1.3+) Java Plugin
if ( (javaVersion != null) && (javaVersion.indexOf("1.3") != -1) ) {
pluginDetected = true;
if (pluginDetected) {
// show applet page
} else if (confirm("Java Plugin 1.3+ not found, Do you want to download it?")) {
// show install page
} else {
// show error page
}

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Hi all,
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CREATE CONTROLFILE REUSE DATABASE "O10G1 NORESETLOGS NOARCHIVELOG
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MAXLOGMEMBERS 3
MAXDATAFILES 100
MAXINSTANCES 8
MAXLOGHISTORY 454
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GROUP 2 'E:\ORACLE2\PRODUCT\10.1.0\ORADATA\O10G1\REDO02.LOG' SIZE 10M,
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DATAFILE
'E:\ORACLE2\PRODUCT\10.1.0\ORADATA\O10G1\SYSTEM01.DBF',
'E:\ORACLE2\PRODUCT\10.1.0\ORADATA\O10G1\UNDOTBS01.DBF',
'E:\ORACLE2\PRODUCT\10.1.0\ORADATA\O10G1\SYSAUX01.DBF',
'E:\ORACLE2\PRODUCT\10.1.0\ORADATA\O10G1\USERS01.DBF'
CHARACTER SET WE8MSWIN1252
Change the new database name abc
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Save as C1.sql
C:\ set oracle_sid=instance name
C:\>sqlplus /nolog
SQL*Plus: Release 10.1.0.2.0 - Production on Tue Apr
11 06:44:28 2006
Copyright (c) 1982, 2004, Oracle. All rights reserved.
SQL> connect / as sysdba;
Connected to an idle instance.
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Variable Size 145750508 bytes
Database Buffers 25165824 bytes
Redo Buffers 262144 bytes
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Hi all,
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myObject-attr2 = 2.
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data: myObject type ref to AAAA,
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myObject-attr1 = 1
myObject-attr2 = 2.
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if oldHash NE newHash.
* MyObject has been modified
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hi i want to know how to detect browser crash or the way to go about it , i can use any language to any api's plz specify me some solution .It would be really healpfull

paul_123 wrote: hi i want to know how to detect browser crash ..
Like the other person that replied, I do not quite understand why it is of interest that the end user's browser crashes. If, like they suspect, it is to do with your applet, I think the best solution is to launch the applet using webstart and forget the browser. If the end user launches a webstart based applet from the browser and the browser crashes, the applet will keep working just fine.
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Edited by: America on Jan 18, 2009 12:03 PM

1. I can't start it because i don't have init.
recreate init file... you can copy init.ora to init<SID>.ora and then modify DB_NAME and control_files parameters...
2. I can't drop database because i can't start.
You can delete manual by remove datafiles, redo file and control files ... After that use "DBCA" to force remove....
3. I can't recreate database using dbca because the same name somewhere exist
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SYS.DBMS_STANDARD
SYS.DICTIONARY_OBJ_NAME
SYS.DICTIONARY_OBJ_TYPE
SYS.STANDARD

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Can anyone tell me
How to make the oracle forms 10g applet or runtime the size of 1024x768?
Thanks in advans..

Please post your question in Forms Topic
Kamran Agayev A. (10g OCP)
http://kamranagayev.wordpress.com
[Step by Step install Oracle on Linux and Automate the installation using Shell Script |http://kamranagayev.wordpress.com/2009/05/01/step-by-step-installing-oracle-database-10g-release-2-on-linux-centos-and-automate-the-installation-using-linux-shell-script/]

Oracle XML vaidation causes database connection lost.

Schema document:
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:s="http://www.w3.org/2001/XMLSchema" xmlns:xsd="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
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          <xsd:documentation xml:lang="en">
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     <xsd:element name="BDDString" type="xsd:string"/>
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XML document:
<?xml version="1.0" encoding="UTF-8"?>
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<?xml version="1.0" encoding="UTF-8"?>
<BDDString
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Declare
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begin
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*** SCRIPT START : Session:M1GLOBAL_DEV15@MATRIX(5) 3-мар-2005 14:05:41 ***
Start SQL Editor Execution ...
Processing ...
xmlObj := XMLType('<?xml version="1.0" encoding="UTF-8"?>
ORA-03113: end-of-file on communication channel
*** SCRIPT END : Session:M1GLOBAL_DEV15@MATRIX(5) 3-мар-2005 14:08:02 ***
End SQL Editor Execution
Task "SQL Editor Execution": Operation aborted
SQL Editor Execution terminated with errors
Task "SQL Editor Execution" in DoTerminate(): Session Manager: No connection to M1GLOBAL_DEV15@MATRIX
Help!
Question:
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     2)How it to correct?

Hi,
1- what is the Reports version being used?
2- What is the error you are getting?
3- Have you tried to enable reports trace and see what is happening in trace file?
Thanks, Roberto

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Regards
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Terry,
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Let us know if the resolves your issue.
Regards,
Dave

How to Detect Database Conneciton Lost in Applet

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