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  • udhcpc doesn't assign ip address

    - by Diab
    i have a board running linux 2.6.28 and i have one Ethernet interface (eth0) i want dhcp to assign dynamic ip to this interface. i have busybox with udhcpc in the file system and the kernel has the "Pack Socket" enabled so i copied the scripts from "busybox-1.14.1/examples/udhcp" to my board on "/etc/udhcpc/" (i created this directory) and when i run : ifconfig eth0 up the interface is up but without ip address, then running udhcpc -i eth0 -s /etc/udhcpc/sample.script i get the following: note : sample.script contains : "exec /etc/udhcpc/sample.$1" # udhcpc -i eth0 -s /etc/udhcpc/sample.script udhcpc (v1.14.1) started Sending discover... Sending select for 192.168.10.198... Lease of 192.168.10.198 obtained, lease time 691200 but when i check with ifconfig i can see that it didn't assign the ip address to eth0. anyone have an idea why udhcpc didn't assign the ip ? Thanx

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  • basic device that can connect to internet

    - by Hellnar
    Hello, I am looking for a cheap solution to my problem: I need to find either an already existing common device (that is used in restaurants, bars clubs) or a cheap new device that I will distribute to those places, which can connect to internet (via the already existing ethernet or wireless based internet) and do HTTP request/receive response and retrieve information ? (For instance can a POS device connect to internet?) For a project, I need to do identity validation on several restaurants and bars and not all of them have computers. So I will be giving "cheap and easy to use devices" and non-IT personal can use it to do http request to my server and get response. All I can think of is Cell phones and SMS.

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  • How do I install packages like Oracle Java?

    - by Sean
    I've been trying to install various things, and I need some packages that just aren't showing up in Ubuntu's Software Center. In fact, no packages are showing up there, just whole programs. I need to install sun-java6-jre for some of these things, but it's simply not in the Software Center. I had Ubuntu last year (and due to various circumstances, had to get rid of it shortly thereafter) and these things were there then. So why can't I find them now?

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  • Typing Accent Marker in Hebrew on Mac

    - by zarose
    I'm learning ancient Hebrew and wanted to make a document full of the vocabulary words I need to memorize so that I can study during my other classes. I noticed that OSX's built-in Hebrew fonts do not include the accent marker. An example: the word for "darkness" is ??????. To represent that the accent is on the first syllable, there needs to be a < over the first letter. The accent could be in the middle of the word, so I can't just throw < at the front every time. Does anyone have a free font that includes this? Any other elegant solutions are welcome. Edit: I found that it is unicode character 05AB. Is there a way to add that to the built-in Hebrew fonts?

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  • JAVA Script confirmation message on button click

    - by Rajneesh Verma
    HI, some times we stuck that how to show confirmation message to do a server side event for example to delete record message should be “Are you sure you want to delete?” so the simplest option is: Code Snippet < asp : Button ID ="Button1" runat ="server" OnClientClick ="return confirm('Are you sure you want to delete?');" onclick ="Button1_Click" Text ="Delete" /> A small tip :) Thanks…...(read more)

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  • Twitter 2 for Android crash every time I try uploading multi photos [closed]

    - by Hazz
    Hello, I'm using the new Twitter 2 on Android 2.1. Whenever I hit the button which enables me to upload multiple photos in a single tweet, I always get the error "The application Camera (process com.sonyericsson.camera) has stopped unexpectidly. Please try again". However, uploading a single photo using the camera button in Twitter have no problem, it works. My phone is Sony Ericsson x10 mini pro. I tried signing out and back in, same result. Anything I can do to fix this? This is the log info I got using Log Collector: 02-23 15:05:57.328 I/ActivityManager( 1240): Starting activity: Intent { act=com.twitter.android.post.status cmp=com.twitter.android/.PostActivity } 02-23 15:05:57.338 D/PhoneWindow(15095): couldn't save which view has focus because the focused view com.android.internal.policy.impl.PhoneWindow$DecorView@45726938 has no id. 02-23 15:05:57.688 I/ActivityManager( 1240): Displayed activity com.twitter.android/.PostActivity: 340 ms (total 340 ms) 02-23 15:05:59.018 I/ActivityManager( 1240): Starting activity: Intent { act=android.intent.action.PICK typ=vnd.android.cursor.dir/image cmp=com.sonyericsson.camera/com.sonyericsson.album.grid.GridActivity } 02-23 15:05:59.038 I/ActivityManager( 1240): Start proc com.sonyericsson.camera for activity com.sonyericsson.camera/com.sonyericsson.album.grid.GridActivity: pid=15113 uid=10057 gids={1006, 1015, 3003} 02-23 15:05:59.128 I/dalvikvm(15113): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=38) 02-23 15:05:59.158 I/dalvikvm(15113): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=50) 02-23 15:05:59.448 I/ActivityManager( 1240): Displayed activity com.sonyericsson.camera/com.sonyericsson.album.grid.GridActivity: 423 ms (total 423 ms) 02-23 15:05:59.458 W/dalvikvm(15113): threadid=15: thread exiting with uncaught exception (group=0x4001e160) 02-23 15:05:59.458 E/AndroidRuntime(15113): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception 02-23 15:05:59.468 E/AndroidRuntime(15113): java.lang.RuntimeException: An error occured while executing doInBackground() 02-23 15:05:59.468 E/AndroidRuntime(15113): at android.os.AsyncTask$3.done(AsyncTask.java:200) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.lang.Thread.run(Thread.java:1096) 02-23 15:05:59.468 E/AndroidRuntime(15113): Caused by: java.lang.IllegalArgumentException: Unsupported MIME type. 02-23 15:05:59.468 E/AndroidRuntime(15113): at com.sonyericsson.album.grid.GridActivity$AlbumTask.doInBackground(GridActivity.java:202) 02-23 15:05:59.468 E/AndroidRuntime(15113): at com.sonyericsson.album.grid.GridActivity$AlbumTask.doInBackground(GridActivity.java:124) 02-23 15:05:59.468 E/AndroidRuntime(15113): at android.os.AsyncTask$2.call(AsyncTask.java:185) 02-23 15:05:59.468 E/AndroidRuntime(15113): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 02-23 15:05:59.468 E/AndroidRuntime(15113): ... 4 more 02-23 15:05:59.628 E/SemcCheckin(15113): Get crash dump level : java.io.FileNotFoundException: /data/semc-checkin/crashdump 02-23 15:05:59.628 W/ActivityManager( 1240): Unable to start service Intent { act=com.sonyericsson.android.jcrashcatcher.action.BUGREPORT_AUTO cmp=com.sonyericsson.android.jcrashcatcher/.JCrashCatcherService (has extras) }: not found 02-23 15:05:59.648 I/Process ( 1240): Sending signal. PID: 15113 SIG: 3 02-23 15:05:59.648 I/dalvikvm(15113): threadid=7: reacting to signal 3 02-23 15:05:59.778 I/dalvikvm(15113): Wrote stack trace to '/data/anr/traces.txt' 02-23 15:06:00.388 E/SemcCheckin( 1673): Get Crash Level : java.io.FileNotFoundException: /data/semc-checkin/crashdump 02-23 15:06:01.708 I/DumpStateReceiver( 1240): Added state dump to 1 crashes 02-23 15:06:02.008 D/iddd-events( 1117): Registering event com.sonyericsson.idd.probe.android.devicemonitor::ApplicationCrash with 4314 bytes payload. 02-23 15:06:06.968 D/dalvikvm( 1673): GC freed 661 objects / 126704 bytes in 124ms 02-23 15:06:11.928 D/dalvikvm( 1379): GC freed 19753 objects / 858832 bytes in 84ms 02-23 15:06:13.038 I/Process (15113): Sending signal. PID: 15113 SIG: 9 02-23 15:06:13.048 I/WindowManager( 1240): WIN DEATH: Window{4596ecc0 com.sonyericsson.camera/com.sonyericsson.album.grid.GridActivity paused=false} 02-23 15:06:13.048 I/ActivityManager( 1240): Process com.sonyericsson.camera (pid 15113) has died. 02-23 15:06:13.048 I/WindowManager( 1240): WIN DEATH: Window{459db5e8 com.sonyericsson.camera/com.sonyericsson.album.grid.GridActivity paused=false} 02-23 15:06:13.078 I/UsageStats( 1240): Unexpected resume of com.twitter.android while already resumed in com.sonyericsson.camera 02-23 15:06:13.098 W/InputManagerService( 1240): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@456e7168 02-23 15:06:21.278 D/dalvikvm( 1745): GC freed 2032 objects / 410848 bytes in 60ms

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  • Browser-based Operating System

    - by Ross Peoples
    I have a bunch of touchscreen machines that I want to display a webpage on and have users interact with the webpage via the touchscreen. Right now, this is done with a full-blown OS with a browser set to run at startup. I think maybe the ideal solution is to use a Linux-based OS that boots up, starts X, then starts a web browser (Chrome, Firefox, or whatever) in full screen mode. What kind of options do I have? I really want to avoid using a full-blown OS like I do now. It looks unprofessional and takes a while to boot up. I was thinking maybe Chrome OS or something, but I wouldn't know how to set it up for my purposes, since it's still designed to be used as a desktop OS instead of a kiosk-type OS.

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  • Slow Starting DHCP Client Service - HP Thin Clients

    - by Ryan
    We have recently began adding XPe thin clients to our domain in preperation for a new citrix environment. One thing that has been picked up on in testing is that they appear slow to boot. The issue manifest's it's self as the classic "Applying Computer Settings..." screen we are all used to seeing. After digging into the issue it appears the DHCP Client service is taking some time to load on boot, this varies but I would estimate it can take around 1 minute in some cases. I've eliminated the classic issues, DHCP is responding correctly and in quick time. DNS is not the cause and GPO's are applying promptly. A simple workaround is to assign the client a static IP which work's great so the TCP/IP servies are obviously firing up quickly, just not DHCP Client. Does anyone have any idea's on how I may be able to improve the service start time? Keen to find a better solution before I get my arm twisted into setting up 250 thin clients with static addressing!

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  • Software design methods for Java or any other programming language

    - by IkerB
    I'm junior programmer and I would like to know how professionals write their code or which steps they follow when they are creating new software. I mean, which steps they follow, which programming methodology, software architecture design application software, etc. I would like to find a tutorial where they explain from the beginning which steps I have to follow from The Idea I have in my mind to the final version of the application in any language. Or perhaps how is your programming steps or rules that you used to follow. Because everytime I want to create the an application I spend few time on the design and a lot of time coding (I know, that's not good).

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  • Sortie de Sonar 2.1, l'outil de qualimétrie logicielle Open Source pour les projets Java par SonarSo

    Bonjour, SonarSource a annoncé la release de Sonar 2.1 qui correspond à un lot de 51 améliorations / corrections dont des fonctionnalités comme :plugin "Squid" : de nouvelles règles pour détecter les méthodes private/protected non utilisées ainsi que les appels de méthodes dépréciées nouvelle page "Libraries" permettant de restituer les librairies utilisées (projets Maven) nouvelle page "Dependencies" pour rechercher les projets utilisant une version donnée d'une librairie nouvelle page "System Info" permettant d'auditer le système (plugins installés, statistiques de la base de données et de la JVM, etc.) Que pensez-vous de Sonar ? Quelles fonctionnalités lui apporteraient de la vale...

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  • Oracle Forms and Java JRE Auto-Update Problems

    - by Grant Ronald
    There have been a few threads regarding problems with the auto update of the JRE and Oracle Forms applications.  See this entry from Steve Chan and this entry on the error FRM-92095: Oracle Jnitiator version too low - please install version 1.1.8.2 or higher.  There are a few points to be aware of so Support have written up a note to hopefully make things clearer.  Log onto your Oracle support account and search for Note: 1470123.1.

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  • Has anyone evaluated NuttX RTOS?

    - by DoxaLogos
    While reading Linux User's Journal today, I stumbled across a little blurb about NuttX RTOS. I checked out their website and was fairly impressed with its feature set and its ability to put it in an 8052! I find it interesting that it supports POSIX which is something I have helped worked on for one of my clients in-house RTOS. This one seems a little more feature rich than the in-house RTOS. Has anyone else heard of NuttX and has given it a try? If so, how does it compare to other RTOS's such as FreeRTOS?

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  • Offline web font optimization tool

    - by avok00
    I have a few web fonts on my web site that I want to reduce in size. I tried http://www.fontsquirrel.com/fontface/generator with very good results, but I need an offline professional tool to rely on. Can somebody recommend such a tool? I am not a specialist font creator, so I need something like a wizard that can guide me through font optimization. Any suggestion is much appretiated! EDIT: To make myself more clear, I need a font subsetting tool

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  • JBoss https on port other than 8080 not working

    - by MilindaD
    We have a server with two JBoss instances where one runs on 8080, the other on 8081. We need to have HTTPS enabled for the 8081 server, firstly we tried enabling https on the 8080 port instance by generating the keystore and editing the server.xml and it successfully worked. However when we tried the same thing for 8081 it did not, note that we removed https for the 8080 server first before enabling it for 8081. This is what was used for both server.xml for 8080 and 8081. The only difference was that the port was changed from 8080 to 8081 when trying to enable https for 8081 port instance. What am I doing wrong and what needs to be changed? NOTE : When I meant enabled for 8080 I meant when you visit https:// URL:8484 you will actually be visiting the 8080 port instance. However when ssl is enabled for 8081 and I visit https:// URL:8484 I get that the web page is unavailable. COMMENTLESS VERSION <Server> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <Listener className="org.apache.catalina.core.JasperListener" /> <Service name="jboss.web"> <!-- https --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- https1 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server> WITH COMMENTS VERSION <Server> <!--APR library loader. Documentation at /docs/apr.html --> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html --> <Listener className="org.apache.catalina.core.JasperListener" /> <!-- Use a custom version of StandardService that allows the connectors to be started independent of the normal lifecycle start to allow web apps to be deployed before starting the connectors. --> <Service name="jboss.web"> <!-- A "Connector" represents an endpoint by which requests are received and responses are returned. Documentation at : Java HTTP Connector: /docs/config/http.html (blocking & non-blocking) Java AJP Connector: /docs/config/ajp.html APR (HTTP/AJP) Connector: /docs/apr.html Define a non-SSL HTTP/1.1 Connector on port 8080 --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <!-- Define a SSL HTTP/1.1 Connector on port 8443 This connector uses the JSSE configuration, when using APR, the connector should be using the OpenSSL style configuration described in the APR documentation --> <!-- <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" keystoreFile="${jboss.server.home.dir}/conf/zara.keystore" keystorePass="zara2010" clientAuth="false" sslProtocol="TLS" compression="on" /> --> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- Define an AJP 1.3 Connector on port 8009 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <!-- The JAAS based authentication and authorization realm implementation that is compatible with the jboss 3.2.x realm implementation. - certificatePrincipal : the class name of the org.jboss.security.auth.certs.CertificatePrincipal impl used for mapping X509[] cert chains to a Princpal. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles --> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <!-- A subclass of JBossSecurityMgrRealm that uses the authentication behavior of JBossSecurityMgrRealm, but overrides the authorization checks to use JACC permissions with the current java.security.Policy to determine authorized access. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles <Realm className="org.jboss.web.tomcat.security.JaccAuthorizationRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> --> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <!-- Uncomment to enable request dumper. This Valve "logs interesting contents from the specified Request (before processing) and the corresponding Response (after processing). It is especially useful in debugging problems related to headers and cookies." --> <!-- <Valve className="org.apache.catalina.valves.RequestDumperValve" /> --> <!-- Access logger --> <!-- <Valve className="org.apache.catalina.valves.AccessLogValve" prefix="localhost_access_log." suffix=".log" pattern="common" directory="${jboss.server.log.dir}" resolveHosts="false" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host. Does not provide SSO across a cluster. If this valve is used, do not use the JBoss ClusteredSingleSignOn valve shown below. A new configuration attribute is available beginning with release 4.0.4: cookieDomain configures the domain to which the SSO cookie will be scoped (i.e. the set of hosts to which the cookie will be presented). By default the cookie is scoped to "/", meaning the host that presented it. Set cookieDomain to a wider domain (e.g. "xyz.com") to allow an SSO to span more than one hostname. --> <!-- <Valve className="org.apache.catalina.authenticator.SingleSignOn" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host AND to all other hosts in the cluster. If this valve is used, do not use the standard Tomcat SingleSignOn valve shown above. Valve uses a JBossCache instance to support SSO credential caching and replication across the cluster. The JBossCache instance must be configured separately. By default, the valve shares a JBossCache with the service that supports HttpSession replication. See the "jboss-web-cluster-service.xml" file in the server/all/deploy directory for cache configuration details. Besides the attributes supported by the standard Tomcat SingleSignOn valve (see the Tomcat docs), this version also supports the following attributes: cookieDomain see above treeCacheName JMX ObjectName of the JBossCache MBean used to support credential caching and replication across the cluster. If not set, the default value is "jboss.cache:service=TomcatClusteringCache", the standard ObjectName of the JBossCache MBean used to support session replication. --> <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <!-- Check for unclosed connections and transaction terminated checks in servlets/jsps. Important: The dependency on the CachedConnectionManager in META-INF/jboss-service.xml must be uncommented, too --> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server>

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  • Multiple Java EE Agents on Single Managed Server

    - by tina.wang
    A default JEE agent is created when you create domain, which is named as OracleDIAgent. 1. In Studio, duplicate the agent, change its name to genAgent, change the web application context to genagent. 2: Go to datasource of genAgent, drop all datasources.3: Generate server template. put the jar file under odi\common\templates\wls 4: Deploy this template by update the existing domain. Bring up the config.cmd, choose update existing domain. 5: Update the domain using the template that just generated. Go through the Configuration wizard. (I did not modify anything or configure anything here). 6: The wizard will give information says the deployment was successful. 7: Bring up the admin server and ODI_server1. 

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  • Tech Article: Tired of Null Pointer Exceptions? Use Java SE 8's Optional!

    - by Tori Wieldt
    A wise man once said you are not a real Java programmer until you've dealt with a null pointer exception. The null reference is the source of many problems because it is often used to denote the absence of a value. Java SE 8 introduces a new class called java.util.Optional that can alleviate some of these problems. In the tech article "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!" Java expert Raoul-Gabriel Urma shows you how to make your code more readable and protect it against null pointer exceptions. Urma explains "The purpose of Optional is not to replace every single null reference in your codebase but rather to help design better APIs in which—just by reading the signature of a method—users can tell whether to expect an optional value. In addition, Optional forces you to actively unwrap an Optional to deal with the absence of a value; as a result, you protect your code against unintended null pointer exceptions." Learn how to go from writing painful nested null checks to writing declarative code that is composable, readable, and better protected from null pointer exceptions. Read "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!"

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  • Virtual Developer Day - EMEA-friendly time

    - by Tori Wieldt
    OTN's Virtual Developer Day lets you learn about the latest technical improvements in Java without leaving your desk/couch/park bench. Watch informative tutorials on your laptop and improve your Java programming expertise and engage in live chat sessions with Java experts, all for FREE.  OTN Virtual Developer Day: Java Europe/Africa/Middle East - June 25 09:00 to 13:00 BST / 10:00 to 14:00 CEST / 13:30 to 17:30 IST / 12:00 to 16:00 MSK / 08:00 to 12:00 Corresponding UTC (GMT) After a short keynote, you can dive into one of these three tracks:  Java SE 8 Track Learn about the features scheduled for Java SE 8, including Lambda expressions, extension methods for interfaces and a new Date and Time API. Learn how to create basic apps with JavaFX.  Java EE Track Take a close look at the new functionality in Java EE 7. Get presentations and demos on JSON, WebSockets, Batch, Concurrency, JAX-RS 2, JMS 2,  Java Embedded Track Provides an introductions to the Raspberry Pi, the Keil board, ARM architecture, and how to make it all work with Java Embedded. You know Java, now really know Java. Register now!

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  • How to build a cheap and fanless server

    - by dag729
    Any advice about how to build a cheap and fanless server? It's main uses would be web and file servering, but it could be a day when I'd like to add some streaming and mailing capabilities as well. OS of choice: GNU/Linux Thanks in advance

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  • Java @Contented annotation to help reduce false sharing

    - by Dave
    See this posting by Aleksey Shipilev for details -- @Contended is something we've wanted for a long time. The JVM provides automatic layout and placement of fields. Usually it'll (a) sort fields by descending size to improve footprint, and (b) pack reference fields so the garbage collector can process a contiguous run of reference fields when tracing. @Contended gives the program a way to provide more explicit guidance with respect to concurrency and false sharing. Using this facility we can sequester hot frequently written shared fields away from other mostly read-only or cold fields. The simple rule is that read-sharing is cheap, and write-sharing is very expensive. We can also pack fields together that tend to be written together by the same thread at about the same time. More generally, we're trying to influence relative field placement to minimize coherency misses. Fields that are accessed closely together in time should be placed proximally in space to promote cache locality. That is, temporal locality should condition spatial locality. Fields accessed together in time should be nearby in space. That having been said, we have to be careful to avoid false sharing and excessive invalidation from coherence traffic. As such, we try to cluster or otherwise sequester fields that tend to written at approximately the same time by the same thread onto the same cache line. Note that there's a tension at play: if we try too hard to minimize single-threaded capacity misses then we can end up with excessive coherency misses running in a parallel environment. Theres no single optimal layout for both single-thread and multithreaded environments. And the ideal layout problem itself is NP-hard. Ideally, a JVM would employ hardware monitoring facilities to detect sharing behavior and change the layout on the fly. That's a bit difficult as we don't yet have the right plumbing to provide efficient and expedient information to the JVM. Hint: we need to disintermediate the OS and hypervisor. Another challenge is that raw field offsets are used in the unsafe facility, so we'd need to address that issue, possibly with an extra level of indirection. Finally, I'd like to be able to pack final fields together as well, as those are known to be read-only.

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  • Russian Hydrodynamic Modeling, Prediction, and Visualization in Java

    - by Geertjan
    JSC "SamaraNIPIoil", located in Samara, Russia, provides the following applications for internal use. SimTools. Used to create & manage reservoir history schedule files for hydrodynamic models. The main features are that it lets you create/manage schedule files for models and create/manage well trajectory files to use with schedule files. DpSolver. Used to estimate permeability cubes using pore cube and results of well testing. Additionally, the user visualizes maps of vapor deposition polymerization or permeability, which can be visualized layer by layer. The base opportunities of the application are that it enables calculation of reservoir vertical heterogeneity and vertical sweep efficiency; automatic history matching of sweep efficiency; and calculations using Quantile-Quantile transformation and vizualization of permeability cube and other reservoir data. Clearly, the two applications above are NetBeans Platform applications.

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