How to be an expert on java?

I work hard on java but everytime I search through community discussions, I feel I know very little. I will be greatful if someone will give me clues about the topics to concantrate on.
Ragards,
Dirgen

what about reading all of them ?
it would be useful to you if you know everything discussed in the forum.
look every day some times at the forum and you'll learn a lot. ;-)
tobias

Similar Messages

How to call C++ module in Java? Can I do it?

Any expert know it, please tell me. Thanks!
I can make the C++ module into a dll, but how can I call it in Java...........
:(

http://java.sun.com/j2se/1.3/docs/guide/jni/index.html

Language experts: Port Java Code to AS3?

Hello out there,
I have been asked whether it would be feasable to translate Java code to AS3. This is a bit difficult since I am not really an expert in Java and only a beginner wrt AS3. Looking at some code samples it seems doable (at least in principle), but of course there might be hidden gotchas lurking. Hence:
- Are there Java features which do not have an equivalent in AS3?
- Does AS3 have prerequisites which do not exist in Java?
- Other aspects to consider?
Any comment or advice will be greatly appreciated.
Best regards
H.

Thanks to you all.
In the meantime I read "Actionscript for Java developers"
http://www.javaworld.com/javaworld/jw-02-2009/jw-02-actionscript1.html
and it seems like the two languages are not too far apart.
Of course there are differences, but we only need to consider those features which Java has and AS has not (like method overloading) and modify our Java sources to not use these. Since the goal is not to have a universal tool which translates _any_ kind of Java source to AS but only our specific code base I think it will be worth a small effort to test how far we get with a machine translation.
Yes, libraries may well be an issue - but again, I would have to see which (library) functions are actually used and how to replace them.
Thanks again and best regards
H.

How to create webservice in Webdynpro java

Hi Experts,
I need to develop one application in Visual Composer.Since VC doesn't support coding so i need to create Webservice in webdynpro java and use that webservice in VC.Can any one of you please suggest how to create Webservice in Webdynpro Java.
Regards,
Prasanna.

Hi prasanna,
Refer this links.
/people/sridhar.k2/blog/2006/09/12/creating-and-exposing-bapi-as-web-service-and-using-it-in-web-dynpro
BAPI Exposed as Web Service
Connect R/3 from Java web application
Web Dynpro integration with R/3
http://help.sap.com/saphelp_nw04s/helpdata/en/82/6a0e7bbe744276bf393654b9b576ed/frameset.htm
Regards,
karthik.

How to print a text in java?

How to print a text in java?

of corse, i have JTextField in my frame that i want to extract the text and print it on a paper with a printer.

How to compile and register a Java CFX tag with multiple class files?

All-
If this is the wrong forum for CFX questions, please let me
know.
I need to determine how to compile and register a Java CFX
tag that contains multiple class files. One class file implements
the CustomTag interface and the other class files implement various
supporting classes. All of the documentation that I have found
talks about using a single class file. I am assuming that a JAR
file will be involved, but I am not sure of the specifics.
Thanks in advance for your help.
-Josh

Yes, it will involve a jar. Use your java IDE (eclipse,
etcetera ..) to create a jar containing all of the classes. Check
your ide's documentation for how to create jar files. After you
have created the jar, place the jar in the CF class path so CF will
recognize it. For example the {cf_root}/WEB-INF/lib directory. CF
must be restarted before it will detect the new jar. After
restarting CF, register the CFX tag in the ColdFusion Administrator
using the name of the class that implements the CustomTag
interface.
Though it is worth noting you can also instantiate java
classes directly from ColdFusion (ie without using a CFX
tag).

How to clear the screen in java?

Hi,
How to clear the screen in java without using any loops?
Thanks

Just paint with your background color to let the old paintings vanish.

How to change system time through java program

Hi
I want to know, how to change system time through java program.
give me a idia with example.
Thanks

There isn't any core Java API for this. Use JNI or call an external process with Runtime.exec().
~

How to set proxy authentication using java properties at run time

Hi All,
How to set proxy authentication using java properties on the command line, or in Netbeans (Project => Properties
=> Run => Arguments). Below is a simple URL data extract program which works in absence of firewall:
import java.io.*;
import java.net.*;
public class DnldURLWithoutUsingProxy {
   public static void main (String[] args) {
      URL u;
      InputStream is = null;
      DataInputStream dis;
      String s;
      try {
          u = new URL("http://www.yahoo.com.au/index.html");
         is = u.openStream();         // throws an IOException
         dis = new DataInputStream(new BufferedInputStream(is));
         BufferedReader br = new BufferedReader(new InputStreamReader(dis));
      String strLine;
      //Read File Line By Line
      while ((strLine = br.readLine()) != null)      {
      // Print the content on the console
          System.out.println (strLine);
      //Close the input stream
      dis.close();
      } catch (MalformedURLException mue) {
         System.out.println("Ouch - a MalformedURLException happened.");
         mue.printStackTrace();
         System.exit(1);
      } catch (IOException ioe) {
         System.out.println("Oops- an IOException happened.");
         ioe.printStackTrace();
         System.exit(1);
      } finally {
         try {
            is.close();
         } catch (IOException ioe) {
}However, it generated the following message when run behind the firewall:
cd C:\Documents and Settings\abc\DnldURL\build\classes
java -cp . DnldURLWithoutUsingProxy
Oops- an IOException happened.
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:305)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:171)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:158)
at java.net.Socket.connect(Socket.java:452)
at java.net.Socket.connect(Socket.java:402)
at sun.net.NetworkClient.doConnect(NetworkClient.java:139)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:402)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:618)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:306)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:267)
at sun.net.www.http.HttpClient.New(HttpClient.java:339)
at sun.net.www.http.HttpClient.New(HttpClient.java:320)
at sun.net.www.http.HttpClient.New(HttpClient.java:315)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:510)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:487)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:615) at java.net.URL.openStream(URL.java:913) at DnldURLWithoutUsingProxy.main(DnldURLWithoutUsingProxy.java:17)
I have also tried the command without much luck either:
java -cp . -Dhttp.proxyHost=wwwproxy -Dhttp.proxyPort=80 DnldURLWithoutUsingProxy
Oops- an IOException happened.
java.io.IOException: Server returned HTTP response code: 407 for URL: http://www.yahoo.com.au/index.html
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1245) at java.net.URL.openStream(URL.java:1009) at DnldURLWithoutUsingProxy.main(DnldURLWithoutUsingProxy.java:17)
All outgoing traffic needs to use the proxy wwwproxy (alias to http://proxypac/proxy.pac) on port 80, where it will prompt for valid authentication before allowing to get through.
There is no problem pinging www.yahoo.com from this system.
I am running jdk1.6.0_03, Netbeans 6.0 on Windows XP platform.
I have tried Greg Sporar's Blog on setting the JVM option in Sun Java System Application Server (GlassFish) and
Java Control Panel - Use browser settings without success.
Thanks,
George

Hi All,
How to set proxy authentication using java properties on the command line, or in Netbeans (Project => Properties
=> Run => Arguments). Below is a simple URL data extract program which works in absence of firewall:
import java.io.*;
import java.net.*;
public class DnldURLWithoutUsingProxy {
   public static void main (String[] args) {
      URL u;
      InputStream is = null;
      DataInputStream dis;
      String s;
      try {
          u = new URL("http://www.yahoo.com.au/index.html");
         is = u.openStream();         // throws an IOException
         dis = new DataInputStream(new BufferedInputStream(is));
         BufferedReader br = new BufferedReader(new InputStreamReader(dis));
      String strLine;
      //Read File Line By Line
      while ((strLine = br.readLine()) != null)      {
      // Print the content on the console
          System.out.println (strLine);
      //Close the input stream
      dis.close();
      } catch (MalformedURLException mue) {
         System.out.println("Ouch - a MalformedURLException happened.");
         mue.printStackTrace();
         System.exit(1);
      } catch (IOException ioe) {
         System.out.println("Oops- an IOException happened.");
         ioe.printStackTrace();
         System.exit(1);
      } finally {
         try {
            is.close();
         } catch (IOException ioe) {
}However, it generated the following message when run behind the firewall:
cd C:\Documents and Settings\abc\DnldURL\build\classes
java -cp . DnldURLWithoutUsingProxy
Oops- an IOException happened.
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:305)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:171)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:158)
at java.net.Socket.connect(Socket.java:452)
at java.net.Socket.connect(Socket.java:402)
at sun.net.NetworkClient.doConnect(NetworkClient.java:139)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:402)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:618)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:306)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:267)
at sun.net.www.http.HttpClient.New(HttpClient.java:339)
at sun.net.www.http.HttpClient.New(HttpClient.java:320)
at sun.net.www.http.HttpClient.New(HttpClient.java:315)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:510)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:487)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:615) at java.net.URL.openStream(URL.java:913) at DnldURLWithoutUsingProxy.main(DnldURLWithoutUsingProxy.java:17)
I have also tried the command without much luck either:
java -cp . -Dhttp.proxyHost=wwwproxy -Dhttp.proxyPort=80 DnldURLWithoutUsingProxy
Oops- an IOException happened.
java.io.IOException: Server returned HTTP response code: 407 for URL: http://www.yahoo.com.au/index.html
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1245) at java.net.URL.openStream(URL.java:1009) at DnldURLWithoutUsingProxy.main(DnldURLWithoutUsingProxy.java:17)
All outgoing traffic needs to use the proxy wwwproxy (alias to http://proxypac/proxy.pac) on port 80, where it will prompt for valid authentication before allowing to get through.
There is no problem pinging www.yahoo.com from this system.
I am running jdk1.6.0_03, Netbeans 6.0 on Windows XP platform.
I have tried Greg Sporar's Blog on setting the JVM option in Sun Java System Application Server (GlassFish) and
Java Control Panel - Use browser settings without success.
Thanks,
George

How to run ear file in java application server

i want how to run .ear file in java application server
1. i m created ear file
2. i m created jar file (bean,home,remote)
3.i m created war file(in the form of jsp)
but till now i couldnt run ear file
how to run
please hel me

You must create :
1.Jar file
2.War file
And then put them into an ear file
Exemple : myapp.ear contains
myappEJB.jar
myappWEB.war
META-INF/application.xml
and application.xml looks like this :
<application xmlns="http://java.sun.com/xml/ns/j2ee" version="1.4"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com /xml/ns/j2ee
                        http://java.sun.com/xml/ns/j2ee/application_1_4.xsd">
    <display-name>myapp</display-name>
    <description>Demo application</description>
    <module>
        <ejb>myappEJB.jar</ejb>
    </module>
    <module>
      <web>
         <web-uri>myappWAR.war</web-uri>
         <context-root>/myapp</context-root>
      </web>
    </module>
</application>Good luck

How To Read RTF file in JAVA? Using iText?

How To Read RTF file in JAVA? Using iText?.....
import java.io.*;
import com.lowagie.text.*;
import com.lowagie.text.rtf.*;
public class RTF3 {
public static void main(String[] args) {
// System.out.println("This example generate a RTF file name Sample.rtf");
// Create Document object
Document myDoc = new Document();
try {
// Create writer to listen document object
// and directs RTF Stream to the file Sample.rtf
RtfWriter2.getInstance(myDoc, new FileOutputStream("Sample.rtf"));
// open the document object
myDoc.open();
// Create a paragraph
     Paragraph p = new Paragraph();
     p.add("Helloworld in Rtf file..amazing isn't");
     // Add the paragraph to document object
myDoc.add(p);
catch(Exception e) {
System.out.println(e);
//close the document
myDoc.close();
Exception in thread "main" java.lang.NoSuchMethodError: com.lowagie.text.Rectangle.width()F
     at com.lowagie.text.rtf.document.RtfPageSetting.rectEquals(RtfPageSetting.java:433)
     at com.lowagie.text.rtf.document.RtfPageSetting.guessFormat(RtfPageSetting.java:362)
     at com.lowagie.text.rtf.document.RtfPageSetting.setPageSize(RtfPageSetting.java:341)
     at com.lowagie.text.rtf.RtfWriter2.setPageSize(RtfWriter2.java:248)
     at com.lowagie.text.Document.open(Unknown Source)
     at view.RTF3.main(RTF3.java:23)
CAN you HELP me?

import com.lowagie.text.Document;
import com.lowagie.text.rtf.parser.RtfParser;
import java.io.FileInputStream;
String inputFile = "sample.rtf";
Document document = new Document();
document.open();
RtfParser parser = new RtfParser(null);
parser.convertRtfDocument(new FileInputStream(inputFile), document);

How to use sql query in java ?

i don't know how to use sql query in java code.
who can give me some advice?
thanks

http://java.sun.com/developer/onlineTraining/Database/JDBC20Intro/

How to create web services in java?

Hi,
I am a newbie to java webservices. Can anybody tell me how to create web services in java?
Any tutorial link or step by step doc would be useful.
Appreciate your help in this regard.
Thanks in advance.
naymo01.

Creating web services in Java appears to depend highly upon the server you intend to use.
Here's a tutorial: http://java.sun.com/webservices/docs/1.6/tutorial/doc/index.html

How many web.xml in a java application

Hi,
can anyone give tell the answer for this question "How many web.xml in a java application?"

1Why ?Because the Web container refers to only one web.xml for one web application.
I havent heard of an application having more than 1 web.xml
How?It reads all the definitions of servlet mappings, filters, welcome-file etc from this file itself.
Where?From the following folder ...
/WEB-INF
By the way ..... the way you questioned me was amuzing ... Why? How ?Where ? Its funny :D
I actually wanted to reply as below ..
Why ?Why not
How?
Wait lemme think ....ummm... What do you mean how??
Where ?
Inside the web ;-)
-Rohit

How to call external files from java?

How to call external files in java. For example how to call a *.pdf file to open in its default editor(say Acrobat), or a *.html file to open in the default browser or a *.txt file in a notepad etc..,
In my program i have *.chm (Compiled Windows HTML Help) help file. how to open it in its default editor it?

Jayarathina_Madharasan wrote:
no one answered my questionHi what wrong did i do...basically insulted all the volunteers here who took the time to consider your question and try to offer you help. Other than that, you did nothing wrong.
From JavaRanch :
And even if an answer doesn't solve your problem, even if it should totally miss the point - the best thing to do to motivate others to continue trying to help you is showing respect and gratitude for the investment of time that was put into dealing with your issue.
Edited by: Encephalopathic on Apr 14, 2008 10:01 AM

How to be an expert on java?

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