Java is essential

Hi all,
As i am new to WDA , is java is essential to learn WDA?
Moreover, i understood automatic JAVA code will generate when creating WD component . Is it true ?
Thanks .
Venkat

hi venkat.........
you can create web dynpro components using java or abap.... so if your going to go on with abap... its not necesary that you need to know java. in both the applcations the code can be automatically generated but anyway you need to define your own logic.
---regards,
alex b justin

Similar Messages

Network UI element and Java 8

Hello everybody!
We are using the "Network" UI element (JNet) in one of our WD Java applications (NW 7.3.1 SP 11). This element consists of an obviously unsigned Java applet (which my local Java 7 JVM complained about for some time). Anyway the applet was working o.k. and the defnied Graphs were rendered (almost) as expected.
Today, I updated my local JVM to Java 1.8.0_45. When using my WebDynpro application, my Browser (IE9) shows the applet area with the Java wait logo, then complains about the unsigned applet as before. When I decide to execute the applet anyway, the applet area turns white, then light blue, but nothing else happens. No graph gets rendered. The same behaviour can be seen using Firefox 32.
The java console essentially shows nothing except the JNet version:
Java-Plug-in 11.45.2.14
JRE-Version verwenden 1.8.0_45-b14 Java HotSpot(TM) Client VM
0
ACF version: 7.1000.1.07
JNet 1.1342.15002
UR L&F version: 7.1000.0.12
What did I do wrong ? Did anyone come across this behaviour ? Is there any patch available that resolves the "unsigned applet" problem or can we get a newer version of this applet somehow ?
Regards
Michael

Hi Ravi!
Yes, we added our portal URL to the JVM security exception list when we upgraded the local JVM to Java 7.
I would like the JNet applet shipped with the WebDynpro runtime to be signed, though, to avoid all these complications. Since the "Network" seems to be an official ui element, I'd expect it to be up to date, to be patched to work with current JVMs and so on. Maybe we missed some notes or patches ?
Regards
Michael

Learning Java in order?

Is there a specific order to learning java. What I mean is, I hava already gone through the fundementals of java at the Java fundementals tutorial on the java.sun.com tutorials page. Now that I have gone through that what is next? JDBC? Servlets? JSP? I hardly ever use swing, or applets, but I need to also study enough of everything so that I can take the java certification exam later. But, I still dont know if there is a learning order to java. Do I need to learn servlets before JSP, or vise versa. Do I need to know JDBC stuff before I learn Servlets or JSP? The java tutorials page is not in any order except in the date that the tutorial came out. They still have tutorial that go back to 1997, and I am sure some things have changed since. They also have specialized areas, such as Collections, JavaBeans, RMI, etc... I am confused on this. Could someone give me a clue.
orozcom

Duffy,
Thanks for the response. I looked at the tutorial
again, and their is another java trail, "Essential
Java Classes", which covers: exception handling,
threads, io reading and writing, setting program
attributes, and accessing system resources. I think I
will go over that information first. Then, I may go
into the specialized trials that have collections and
what not. after that, I think I will go into the J2EE
stuff, doing Servlets, and JSP's unless I need to
learn that stuff before hand. Tell me what you think.I think that's wise.
Here is the site:
http://java.sun.com/docs/books/tutorial/index.html.
Do you think I need to go over the basics of Swing,
Applets, GUI's, and in the order they specify?Personally, I don't use applets at all, but I know some folks here do. On those occasions when I have a UI, it's usually Web-based, so JSP and HTML are more important to me. I have done Swing, but not in a long time. Swing is worth knowing, and all learning is good, but the decision about where to spend your time is up to you.
All I'm saying is make sure you have J2SE firmly in hand before you venture into J2EE, because J2EE builds on J2SE.

Java for oracle dba

Please tell me what all learning of java is essential for orcale 9i dba?
Also intimate the source for the same

You may want to review some of the doc in this area:
http://download.oracle.com/docs/cd/B10501_01/java.920/a96656/toc.htm
Cheers, OTN

Difference between Java and Perl?

I'm new to Java and was wondering what is the difference between Java and Perl. Other than Java has to be compiled and Perl does not. Is one better than the other? Here is a link to my website. The languaged used is Perl. Can Java be used to write a program like this.
http://www.i2r2.co.nr

Perl - interpreted
Java - compiled (essentially -- there is no eval statement)
Perl - lots functionality built into the bare language
Java - more functionality moved into libraries
(both have huge libraries available though -- and Java's core language seems to get bigger with each new release)
Perl - loosely typed
Java - strongly typed
IMHO:
Perl - Baroque ornate language good for quick scripts
Java - Calvinist spartan language good for huge projects
I can't think of anything else to say that can't be expressed in one-liners.

Using ASCII in java

How can i use ascii in java programming. For example i want convert binary to decimal and use operator such XOR etc to campare to another decimal number. After that convert into ascii code.
thank you

If you have a string, then you can convert it into an array of char. Chars are just numbers. (They're numbers that represent unicode characters, but they're still numbers.)
And all the primitive types in java are essentially binary; you don't have to convert anything to binary unless you mean to convert it for display purposes.
If you have a string and want to convert it to ascii, then you can specify the encoding type (ascii) while converting to bytes or writing output to a file, etc.
Hope this helps.

Program in JAVA-ABAP

Can we program in JAVA in mySAP to build an application equivalant to ABAP?
If yes, then how much JAVA is essential? is basics fine? or advance concepts are required?

Theoretically its is definitely possible, but you might face a lot of practical difficulties. For one, all your application tables are in ABAP and for each operation you would have to call the ABAP table. As far as I know, the dictionary-level integration between ABAP and Java is not fully functional yet.
Secondly, each time you would have to do a Jco call to the ABAP engine to pass back values/call an FM in the system, etc. That would add to the time taken by your app.
You would require a very good knowledge of java to be able to code an entire app.
Sudha

Maximum thread in java

I have created a program to check max no of thread in java
public class Test extends Thread {
static int count;
public static void main (String [] args){
for(;;){
count++;
System.out.println(count);
new Test().start();
@Override
public void run() {
try {
Thread.sleep(100000000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
First iteration -Xmx1024m ,max thread = 2011 > Second iteration -Xmx512m ,max thread = 3350 > third iteration -Xmx2m ,max thread = 5112
I have also tried with setting -Xss1m ,max thread = 1011, then I have set -Xss256k max thread 4900+
Can anyone suggest me
1)what is relation of stack and heap size in java?
2)On what factor does max no of thread depends in java?

1)what is relation of stack and heap size in java?Essentially nil.
2)On what factor does max no of thread depends in java?It depends on the operating system, the thread stack size, the amount of virtual memory available, ...

Reading Each String From a text File

Hello everyone...,
I've a doubt in File...cos am not aware of File.....Could anyone
plz tell me how do i read each String from a text file and store those Strings in each File...For example if a file contains "Java Tchnology forums, File handling in Java"...
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The Java� Tutorials > Essential Classes: Basic I/O

Need of exception handler in calling function, isn't that weird???

Hi,
I have written a function as follows
public String fetchName(String query) throws Exception
          stmt = con.createStatement();
          ResultSet rs = stmt.executeQuery(query);
          rs.next();
          return (rs.getString(1));
I've handled the for exceptions here using "throws Exception". Inspite of that when i call it from other function and in that funtion no exception need to be handled, compiler gives errror.
Following is the calling funtion
public String checksubAction(String action)
          String retValue=" ";
String query="";
          query = "select Title from dbo.Folder where Folder_Id="+folderId;
          retValue = dataBaseObj.fetchName(query);
but when i write it in try-catch block, no errror is given.
Why is it that inspite of handling exception(s) in the called function, we need to handle them in calling functions.

No you have not handled the exception. Your code say "fetchName" does NOT handle exceptions of type "Exception", the calling method should be aware of this, and handle that type of exception.
The Java Tutorial: Essential Java Classes: Handling Errors Using Exceptions
(Please when declaring a method can throw exceptions, be specific, i.e. throw SQLException in this case)

Can anyone explain me the following terms.....

Hi all,
Can anyone explain me the following terms in WM
1. WareHouse
2. Storage Bin
3. Storage Location
4. Storage Unit.
5. Handling Units(External/Internal)
Thanks

Hi Kripa,
1. What is Netweaver ?
Click Here: <a href="http://www.thespot4sap.com/Articles/SAP_Netweaver_Introduction.asp">Netweaver: An Introduction</a>
<a href="http://www.sap.com/platform/netweaver/index.epx">http://www.sap.com/platform/netweaver/index.epx</a>
2. What is the difference bet NW 2004 and NW2004s?
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/devguide2004">SAP NetWeaver 2004 Edition</a>
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/devguide2004s">SAP NetWeaver 2004s Edition</a>
3. Is it mandatory to know JAVA language to sustain with NW technologies? or ABAP itself is enough ?
Its all depend in which stack you want to fit. If you want to go into EP, then JAVA is must. In XI having knowledge of JAVA will be highly useful and in other Netweaver stack it will be an added advantage. Anyhow ABAP is not enough to sustain with NW technologies.
<a href="http://www.sap.com/platform/netweaver/standardssupport/java.epx">Netweaver and JAVA</a>
4. If JAVA is essential ...where to start with ?
Core JAVA, J2EE in full is needed for Netweaver. As where to start is concern you can start with core JAVA and consequencely go thorugh J2EE.
I hope this will help you out.
Regards,
Subhasha Ranjan

How can one invoke a WebLogic EJB from a BPEL Server hosted on OC4J?

How can one invoke a WebLogic EJB from a BPEL Server hosted on OC4J?
Reason I ask is I keep getting this error:
javax.naming.NoInitialContextException: Cannot instantiate cla
ss: weblogic.jndi.WLInitialContextFactory [Root exception is java.lang.ClassNotF
oundException: weblogic.jndi.WLInitialContextFactory]
Note: I am using <bpelx:exec> as a way to execute some java program.
Essentially my java client (essentially an EJB client hosted on Oc4J) needs access to wlclient.jar since it needs access to weblogic.jndi.WLInitialContextFactory. I have a EJB client running on BPEL server hosted on Oc4J that needs to access some EJBs hosted on weblogic.
Where do I place this wlclient.jar so that BPEL PM can start peacefully and at runtime discover the InitialContextFactory classes?
Placing it in the j2ee/home/applib doesn't solve the problem. The server fails to start up if I do this
I tried placing it in BPEL-INF\lib directory ...
I still get the same exception...see below for exception dump
I verified the BPEL suitcase, and it in fact does contain the jar file wlclient.jar
integration\orabpel\domains\default\deploy contains the bpel_BPELProcess2_1.0.jar file and snapshot of that is as follows:
<PRE>
│ bpel.xml
│ BPELProcess2.bpel
│ BPELProcess2.jpr
│ BPELProcess2.wsdl
│ bpel_BPELProcess2_1.0.jar
│ build.xml
│ buildxml.copy
│ graphics.xml
│
├───BPEL-INF
│ └───lib
│ myEJB.jar
│ wlclient.jar
│
├───META-INF
│ MANIFEST.MF
│
└───output
bpel_BPELProcess2_1.0.jar
</PRE>
I tried using the BPEL-INF\jar directory...Is this something the obant automatically detects? or do I have to modify the build.xml? I created this directory and let Jdev deploy to local BPEL server->default domain handle it
#####################3
I even tried copying the wlclient.jar to
integration\orabpel\system\classes but this doesn't help since the BPEL PM fails to start if I explode this jar into this directory.
In short,where do I place the wlclient.jar so that this exception can be contained.
I edited the build.xml to point to the jar, that too didn't work, unless I made some mistake in the file
<bpelc classpath="${basedir}/BPEL-INF/classes;${home}/system/classes;${home}/lib/j2ee_1.3.01.jar;${basedir}/BPEL-INF/jar/wlclient.jar" input="${basedir}/bpel.xml" rev="${rev}" deploy="${deploy}" />
</target>
</project>
DETAILS on ERROR
I get the following error
Process "BPELProcess2" (revision "1.0") successfully compiled.
<2005-12-14 09:17:55,770> <INFO> <default.collaxa.cube.engine.deployment> Proces
s "BPELProcess2" (revision "1.0") successfully loaded.
05/12/14 09:18:36 weblogic.jndi.WLInitialContextFactory
javax.naming.NoInitialContextException: Cannot instantiate cla
ss: weblogic.jndi.WLInitialContextFactory [Root exception is java.lang.ClassNotF
oundException: weblogic.jndi.WLInitialContextFactory]
05/12/14 09:18:36 at javax.naming.spi.NamingManager.getInitialContext(Nami
ngManager.java:652)
05/12/14 09:18:36 at javax.naming.InitialContext.getDefaultInitCtx(Initial
Context.java:243)
05/12/14 09:18:36 at javax.naming.InitialContext.init(InitialContext.java:
219)
05/12/14 09:18:36 at javax.naming.InitialContext.<init>(InitialContext.jav
a:195)
05/12/14 09:18:36 at com.ejb.test.MapFinder.getDefaultMapName(Map
Finder.java:37)
##################3
with the bpelx all I have is two lines of code that creates a java object and calls a method on it.
The method does this:
    private String initialContextFactory = "weblogic.jndi.WLInitialContextFactory";
    private String providerUrl = "t3://localhost:7001";
    private String urlPkgPrefixes = "";
    private String mapEjbJndiName = "ejb/mycompany/Redlands";
    public String getDefaultMapName() {
      try {
          Hashtable env = new Hashtable();
          env.put(Context.INITIAL_CONTEXT_FACTORY, getInitialContextFactory());
          env.put(Context.PROVIDER_URL, getProviderUrl());
          if (getUrlPkgPrefixes() != null && !getUrlPkgPrefixes().equals(""))
              env.put(Context.URL_PKG_PREFIXES, getUrlPkgPrefixes());
          System.out.println("    " + getInitialContextFactory());
          System.out.println("    " + getProviderUrl());
          System.out.println("    " + getUrlPkgPrefixes());
          System.out.println("    " + getEjbName());
          // Get a naming context
          context = new InitialContext(env);
           Object ms = context.lookup(getEjbName());
          MyEJBHome home = (MyEJBHome ) PortableRemoteObject.narrow(ms, MyEJBHome.class);
          myEjb = home.create();
          return myEjb.getDefaultName();
      } catch (RemoteException re){
          System.out.println(re.getCause().getMessage());
      catch (Exception ex) {
          ex.printStackTrace();
      return null; //if unable to resolve the context factory etc...
    }

I did exactly as you suggested. I edited the application.xml and added this
<library path="C:\ArcGIS\test\bea\wlclient.jar"/>
I didn't add weblogic because the needed classes were all in wlclient.jar
I also edited the BASE_OB_CLASSPATH to include this jar.
Here is the result when I just start BPEL PM Server. Somehow BPEL PM doesn't like to have wlclient.jar in its classpath during startup.
Failed to create "worker" bean; exception reported is: "javax.naming.NameNotFoun
dException: remaining name: env
at weblogic.j2eeclient.SimpleContext.lookup(SimpleContext.java:49)
at weblogic.j2eeclient.SimpleContext.lookup(SimpleContext.java:57)
at weblogic.j2eeclient.SimpleContext.lookup(SimpleContext.java:62)
at javax.naming.InitialContext.lookup(InitialContext.java:347)
at com.collaxa.cube.engine.ejb.impl.WorkerBean.ejbCreate(WorkerBean.java
:49)
at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at com.evermind.server.ejb.MessageDrivenHome.getInstance(MessageDrivenHo
me.java:1235)
at com.evermind.server.ejb.MessageDrivenHome$2.run(MessageDrivenHome.jav
a:1150)
at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(Relea
sableResourcePooledExecutor.java:186)
at java.lang.Thread.run(Thread.java:534)
<2005-12-29 13:39:05,281> <ERROR> <collaxa> <ServerManager::loadAllDomains>
ORABPEL START-UP ERROR!!!!!!!!
OraBPEL run-time system failed to start due to exception:
Could not initialize jms connection pool.
Could not initialize connection pool for connection factory "java:comp/env/jms/
ollaxa/BPELInvokerQueueFactory"; the reason is remaining name: env/jms/collaxa/
PELInvokerQueueFactory.
Note: So what I did was to removed the entry from application.xml and tried with just obsetenv.bat having the wlclient.jar added to it. This too failed!!
Here is a snapshot of the error I got.
Process "BPELProcess2" (revision "1.0") successfully compiled.
<2005-12-29 13:53:11,207> <INFO> <default.collaxa.cube.engine.deployment> Proces
s "BPELProcess2" (revision "1.0") successfully loaded.
05/12/29 13:53:32 Cannot instantiate class: weblogic.jndi.WLInitialContextFactor
y
05/12/29 13:53:32 javax.naming.NoInitialContextException: Cannot instantiate cla
ss: weblogic.jndi.WLInitialContextFactory [Root exception is java.lang.ClassNotF
oundException: weblogic.jndi.WLInitialContextFactory]
05/12/29 13:53:32 at javax.naming.spi.NamingManager.getInitialContext(Nami
ngManager.java:652)
05/12/29 13:53:32 at javax.naming.InitialContext.getDefaultInitCtx(Initial
Context.java:243)
05/12/29 13:53:32 at javax.naming.InitialContext.init(InitialContext.java:
219)
05/12/29 13:53:32 at javax.naming.InitialContext.<init>(InitialContext.jav
a:195)
05/12/29 13:53:32 at com.esri.adf.ejb.test.MapFinder.getDefaultMapName(Map
Finder.java:57)
05/12/29 13:53:32 at bpel.p0.ExecLetBxExe1.execute(ExecLetBxExe1.java:62)
05/12/29 13:53:32 at com.collaxa.cube.engine.ext.wmp.BPELXExecWMP.__execut
eStatements(BPELXExecWMP.java:49)
05/12/29 13:53:32 at com.collaxa.cube.engine.ext.wmp.BPELActivityWMP.perfo
rm(BPELActivityWMP.java:185)
05/12/29 13:53:32 at com.collaxa.cube.engine.CubeEngine.performActivity(Cu
beEngine.java:3398)
05/12/29 13:53:32 at com.collaxa.cube.engine.CubeEngine.handleWorkItem(Cub
eEngine.java:1905)
05/12/29 13:53:32 at com.collaxa.cube.engine.dispatch.message.instance.Per
formMessageHandler.handleLocal(PerformMessageHandler.java:75)
05/12/29 13:53:32 at com.collaxa.cube.engine.dispatch.DispatchHelper.handl
eLocalMessage(DispatchHelper.java:100)
05/12/29 13:53:32 at com.collaxa.cube.engine.dispatch.DispatchHelper.sendM

WatchService WatchKey.cancel() is really forever ?

I am using java 8 on linux ubuntu 12.04 following the guidelines Watching a Directory for Changes (The Java™ Tutorials > Essential Classes > Basic I/O)
This works but I notice that once I cancel a watchkey with watchkey.cancel() , I seem to be unable to reenable it again. So I can never watch a directory after I have cancelled the corresponding watchkey (even after reboot ) ?
The API Doc says that " Once cancelled, a watch key remains forever invalid."
What does "forever" mean ? There must be a way to re-watch a dir after the key has been cancelled.
Thanks for your help.

Registering recursively will work as Sotirios has indicated. This effectively registers each directory/sub-directory that currently exists.
You can alternatively import and use *com.sun.nio.file.ExtendedWatchEventModifier.FILE_TREE* as in:
dir.register(watcher, standardEventsArray, ExtendedWatchEventModifier.FILE_TREE);
This will watch the entire sub-tree for change AND account for added directories and sub-directories.
Otherwise you will have to monitor for any new directories/sub-directories and register them also. There can also be an issue with deleting parts of the directory hierarchy since each registered directory has a handle watching it so the (lowest) sub-directories need to be removed first when deleting parts of the structure.

Netweaver Basics

Hi Friends,
Iam very very new to Netweaver technology ........
So can anyone explain me in very basic terms to the following questions ...
1. What is Netweaver ?
2. What is the difference bet NW 2004 and NW2004s?
3. Is it mandatory to know JAVA language to sustain with NW technologies? or ABAP itself is enough ?
4. If JAVA is essential ...where to start with ?
Hmm .... yeah these are the questions as of now
Expecting responses ...
Cheers
Kripa Rangachari .....
I dont know where to post the Netweaver general questions ;(

Hi Kripa,
1. What is Netweaver ?
Click Here: <a href="http://www.thespot4sap.com/Articles/SAP_Netweaver_Introduction.asp">Netweaver: An Introduction</a>
<a href="http://www.sap.com/platform/netweaver/index.epx">http://www.sap.com/platform/netweaver/index.epx</a>
2. What is the difference bet NW 2004 and NW2004s?
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/devguide2004">SAP NetWeaver 2004 Edition</a>
<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/devguide2004s">SAP NetWeaver 2004s Edition</a>
3. Is it mandatory to know JAVA language to sustain with NW technologies? or ABAP itself is enough ?
Its all depend in which stack you want to fit. If you want to go into EP, then JAVA is must. In XI having knowledge of JAVA will be highly useful and in other Netweaver stack it will be an added advantage. Anyhow ABAP is not enough to sustain with NW technologies.
<a href="http://www.sap.com/platform/netweaver/standardssupport/java.epx">Netweaver and JAVA</a>
4. If JAVA is essential ...where to start with ?
Core JAVA, J2EE in full is needed for Netweaver. As where to start is concern you can start with core JAVA and consequencely go thorugh J2EE.
I hope this will help you out.
Regards,
Subhasha Ranjan

SAP - XI - JBoss/Tomcat

In the system I'll implement, RFC for enquiries & Idoc for reporting will both be applied accordingly. The system contains a simple java web-app as the front-end deployed on 3rd party J2EE web App server (eg: Tomcat/JBoss) that will connect to SAP-XI then to client's SAP system.
I've been studying on RFC, Idoc & some XI-related overviews lately. I come to realize that what being suggested is deploying java app on SAP J2EE Engine. Since we will be using Tomcat/Apache AS, the mentioned architecture cannot be applied.
So, I hope you can give me a lead on re-designing the whole architecture if required.
1) May I know the suggested system hardware setup for this design? Does J2EE web server & SAP XI reside on the same machine or advisably to be separated?
2) I shifted this post from SAP-XI forum prior to forummer's suggestion. I will develop this system in Eclipse environment as I know SAP provides certain plugins for the integration. May I know what plugins are required?
Note: Now, I still find it hard to compose the whole big picture. My background is fresh Java Programmer with no experience in SAP.

Nothing should prevent you connecting your web app on tomcat to XI , whatever the direction of message flow be i.e. outbound / inbound.
XI has a combination of Java stack as well as ABAP stack as its base. The java stack essentially being the J2EE engine. It resides on the same host as that of XI, at least almost all the XI installations I've seen
Assume that your Web app wants to send as well as recieve data from XI, let us consider case by case :
1. Send data to XI : You need to make your application do a HTTP post into XI pipeline, you do not need any XI adapter to be configured as SENDER XI HTTP adapter is not required.
2. Recieve data from XI : Prerequisite being your web app works on HTTP post , you can configure a reciever HTTP adapter on XI which will send data to your webapp and might / might not recivee response.
For all this development you can use NetWeaver developer studio.

Java is essential

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