Beginning java part 2

hi
following my early message of writing my first HelloWorld programme, I am now trying to open the JVM. Problem is, I don't seem to be able to find it. I have lots of jvm files on my hard drive but they are web pages or text files.
I have also downloaded and installed MSJVM separately but the links are to a set of "Deluxe" "local web pages".
my instructions tell me to run the jvm and type in
C:\src>java -cp . HelloWorld
any help appreciated - just starting out...
thanks
k

Carefully follow the instructions here:
Installation Notes - JDK 5.0 Microsoft Windows (32-bit)
Your First Cup of Java

Similar Messages

Beginning java programmer

I'm currently a computer programming student. I've previously taken VB, & C++. We've just started doing applets in my java class, and I'm really starting to enjoy the language more that previous ones. I was wondering where to I go from here. I've got the jdk 1.3 & editplus2 at home and am doing basic stuff with it. The book that I have goes over the basics,inheritance,understaind awt, layout managers/event model, exeception handling, file input/output, and multithreading and animation. But my class will probably not get through what is covered in this book. I'm moving along nicely at home with it, but what I be learning next? Any books to recommend?(I work at a bookstore so finding them isn't a problem) I'm just looking for some direction. Thanks.

You do not mention what book you have. If you do not have it already I recommend Core JAVA 2 Volume 1 - Fundamentals. The authors are Cay Horstmann and Gary Cornell. It is part of the SUN Microsystems Press Java Series. I used it in Java I. You can probably walk through the book yourself if you are disciplined. It covers all of the basics and the examples get you going.
I also use Beginning Java 2 by Ivor Horton. It was my Intro to Java book. This is also a great for beginners. If I had to recommend between the two I would say Core. It covers most of the same stuff (all plus some if you pick up Core Volume 2) and is easier to read.
Also, do not be a stranger to the trail... http://java.sun.com/docs/books/tutorial/trailmap.html and
tutorials... http://developer.java.sun.com/developer/onlineTraining/new2java/divelog/part1/page9.jsp
A lot of great information there!

We need to reinstall the JAVA part alone in ABAP+JAVA

Dear Sir/Madam,
We have an SAP ECC 6.0 system with ABAP+JAVA components. Now there are some issue with our Java comp. and I'm unable to start the JAVA engine. As we have done little configuration on JAVA side we are planning to reinstall the JAVA part alone.
1)Can we uninstall the the JAVA Component alone from the ABAP+JAVA Central instance?(Without affecting the ABAP Part)
2)Can we install a new JAVA addin in our existing ABAP+JAVA system?
3)If yes; is there any special steps appart from the master guide "4.4.2 Installing the Java Add-In for an Existing ABAP System" ?
Thank you,
Siju

Thank you for the update,
We have done a Homogeneous system copy from our DEV system to QA system(SAP ECC 6.0 ABAP+JAVA with Oracle 10g)
Our issue is we are unable to connect the VA it shows "Unable to lookup connection default".
We've noticed that the Instance ID in our config tool still shows the DEV Instance ID and the Instance.properties files shows the QA system instance ID.
In our DEV it's given
com.sap.engine.bootstrap.Bootstrap
./bootstrap
ID0035522
and QA it's
ID0031354
In have changed the SID,HOST NAME and Instance ID in the config tool to the QA system param. as per the suggestions in the below link
Re: J2EE info status unavailable after system refresh
but still I am unable to connect the VA.
the log JVM_bootstrap.out is given below
Bootstrap MODE:
<INSTANCE GLOBALS>
determined by parameter [ID0031354].
Exception occurred:
com.sap.engine.frame.core.configuration.NameNotFoundException: A configuration with the path "cluster_data/dispatcher/ID3135400" does not exist.
     at com.sap.engine.core.configuration.impl.ConfigurationDataCacheAllImpl.getSubConfiguration(ConfigurationDataCacheAllImpl.java:107)
     at com.sap.engine.core.configuration.impl.ReadAccessConfiguration.getSubConfiguration(ReadAccessConfiguration.java:715)
     at com.sap.engine.bootstrap.Synchronizer.getConfiguration(Synchronizer.java:426)
     at com.sap.engine.bootstrap.Synchronizer.getElementType(Synchronizer.java:72)
     at com.sap.engine.bootstrap.Bootstrap.initDatabaseConnection(Bootstrap.java:420)
     at com.sap.engine.bootstrap.Bootstrap.<init>(Bootstrap.java:144)
     at com.sap.engine.bootstrap.Bootstrap.main(Bootstrap.java:814)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:324)
     at com.sap.engine.offline.OfflineToolStart.main(OfflineToolStart.java:81)
Exception occurred:
com.sap.engine.bootstrap.SynchronizationException: Database initialization failed! Check database properties!
     at com.sap.engine.bootstrap.Bootstrap.initDatabaseConnection(Bootstrap.java:422)
     at com.sap.engine.bootstrap.Bootstrap.<init>(Bootstrap.java:144)
     at com.sap.engine.bootstrap.Bootstrap.main(Bootstrap.java:814)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:324)
     at com.sap.engine.offline.OfflineToolStart.main(OfflineToolStart.java:81)
==[ Caused by: ]==----
com.sap.engine.bootstrap.SynchronizationException: No such Dialog Instance (ID3135400) in the database! Check database consistency or local Bootstrap properties!
     at com.sap.engine.bootstrap.Synchronizer.getElementType(Synchronizer.java:75)
     at com.sap.engine.bootstrap.Bootstrap.initDatabaseConnection(Bootstrap.java:420)
     at com.sap.engine.bootstrap.Bootstrap.<init>(Bootstrap.java:144)
     at com.sap.engine.bootstrap.Bootstrap.main(Bootstrap.java:814)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:324)
     at com.sap.engine.offline.OfflineToolStart.main(OfflineToolStart.java:81)
[Bootstrap module]> Problem occurred while performing synchronization.
Please let me know how to resolve this isse.
Thank you,
Siju
Edited by: Siju Sam on Jul 7, 2009 7:21 AM

How does NetWeaver support FIPS in java part?

As we know, default JDK doesn't support FIPS in the SSL/TLS socket.
There are 3rdpart soft, like certicom, bsafe can support this.
And in the opensource, NSS + jdk, seems can be a solution.
Here, just a question, how does NetWeaver support FIPS in java part? Is there an internal implementation?
Thanks.
Message was edited by: Andy Silvey

I'm not aware of any. The library is backwards compatible so you should be able to replace an existing SAP Cryptographic Library with CommonCryptoLib. The Crypto Kernel implementation seems to exist only for AS ABAP. Maybe someone working on security at SAP can comment, I will ping the Security space to get their attention.

System Refresh Only Java part

Hi Dear Gurus,
I have been given a task to do a system refresh for only java part for BI ( ABAP is already done).
please tell me what are all the precautions that to be taken while doing the java part.
we are running on windows and Mysql.
Please specify the steps that to be performed before doing the java part in the source system and target system.
Many thanks for your time guys.
Kind Regards,
Vamsi.
Edited by: vamsi koganti on Jan 23, 2008 1:11 PM

Hi Dear Rajesh
Many thanks for your reply and your time.
Few more questions
*deleting the contents of the global directory (pleasetell me where it is located)
where to give the CONTROL.SQL file?
and one more problem
I am getting the fallowing error when i start sapinst.exe
starting gui server process:
sapinstport: 21200
guiport    : 21212
guistart   : true
command    : "C:\j2sdk1.4.2_12/bin\javaw.exe" -cp "C:/WINDOWS/TEMP/sapinst_exe.8596.1201160177\jar\instgui.jar;C:/WINDOWS/TEMP/sapinst_exe.8596.1201160177\jar\inqmyxml.jar" -Xmx256M -Dsun.java2d.noddraw=true SDTServer config=jar:sdtserver.xml guiport=21212 sapinsthost=localhost sapinstport=21200 guistart=true
guiengine: call to bind() for socket 21200 1800 failed . No error
103 guiengine.connection.failed 21200, 943
Exit status of child: 1
I look in some previous post they ask the person to check the port is being used or not? how to check the port is being used or not? and how to assign this to that port **************
Please help me rajesh.
Once again many thanks for your time.
kind Regards,
vamsi.
Edited by: vamsi koganti on Jan 24, 2008 8:49 AM

Is there a new version of the book "Beginning Java Web Services"?

I am new to programming web services with Java. Is Beginning Java Web Services a recommended book for a beginner? Does it have a newer version as the one available was written in 2002. Can anyone suggest a latest beginners guide book?

The MD387LL/A, MD388LL/A, and MD389LL/A are the latest models in the USA and Canada. It's the same in other countries, except for the LL.
(102906)

Problems whit java part 2

ok i repeat my problem 'cause i 've not found a solution
this is my class :
* Shell.java
* Created on 14 settembre 2006, 8.39
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
* @author g.veltro
import java.io.*;
public class Shell {
public static final String path_cosisan ="Z:\\\\cdg\\db\\txt\\cosisan";
public static final String totati_medico_sh ="totali_medico.sh";
public static final String controllo_medico= "Medici.ctl";
public static final String par_con ="giord/giord";
     private static final String path_unix_utilities = "c:\\\\unix\\bin\\";
     private static final String path_oradb = "c:\\Programmi\\Oracle\\OraDb\\BIN\\";
     private static final String string_rifiuto = "Totale dei record logici rifiutati:";
     private static final String string_scarto = "Totale dei record logici scartati:";
     public Shell(){
     public static boolean eseguiSQLLDR(String parametri_connessione,String path,String file_controllo){
          try {
          String comando = path_oradb+"sqlldr userid="+parametri_connessione+" control="+file_controllo;
          // Esegui il comando
          Process pr = Runtime.getRuntime().exec(comando,null,new File(path));
          // Cattura dell' output
          BufferedReader br_in = null;
          try {
          br_in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
          String buff = null;
          while ((buff = br_in.readLine()) != null) {
          System.out.println("Output: " + buff);
          Thread.sleep(100);
          br_in.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_in.close();
          // Cattura dell' errore
          BufferedReader br_err = null;
          try {
          br_err = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
          String buff = null;
          while ((buff = br_err.readLine()) != null) {
          System.out.println("Errore : " + buff);
          Thread.sleep(100);
          br_err.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_err.close();
          catch (Exception ex) {
          System.out.println(ex.getLocalizedMessage());
          return Shell.controlloSQLLDR(path,file_controllo);
     public static boolean eseguiSQLLDR(String parametri_connessione,String path,String file_sh,String file_controllo){
          boolean bash = Shell.eseguiComando_Bash(path, file_sh);
          if(!bash) return false;
          try {
          String comando = path_oradb+"sqlldr userid="+parametri_connessione+" control="+file_controllo;
          // Esegui il comando
          Process pr = Runtime.getRuntime().exec(comando,null,new File(path));
          // Cattura dell' output
          BufferedReader br_in = null;
          try {
          br_in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
          String buff = null;
          while ((buff = br_in.readLine()) != null) {
          System.out.println("Output: " + buff);
          Thread.sleep(100);
          br_in.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_in.close();
          // Cattura dell' errore
          BufferedReader br_err = null;
          try {
          br_err = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
          String buff = null;
          while ((buff = br_err.readLine()) != null) {
          System.out.println("Errore : " + buff);
          Thread.sleep(100);
          br_err.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          return false;
          } finally {
          br_err.close();
          catch (Exception ex) {
          System.out.println(ex.getLocalizedMessage());
          return controlloSQLLDR(path,file_controllo);
     public static boolean eseguiComando_Bash(String path,String file_sh) {
          try {
          String comando = Shell.path_unix_utilities+"bash "+file_sh;
          // Esegui il comando
          Process pr = Runtime.getRuntime().exec(comando,null,new File(path));
          // Cattura dell' output
          BufferedReader br_in = null;
          try {
          br_in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
          String buff = null;
          while ((buff = br_in.readLine()) != null) {
          System.out.println("Output: " + buff);
          Thread.sleep(100);
          br_in.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_in.close();
          // Cattura dell' errore
          BufferedReader br_err = null;
          try {
          br_err = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
          String buff = null;
          while ((buff = br_err.readLine()) != null) {
          System.out.println("Errore : " + buff);
          Thread.sleep(100);
          br_err.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          return false;
          } finally {
          br_err.close();
          catch (Exception ex) {
          System.out.println(ex.getLocalizedMessage());
          return true;
     private static String eseguiComando_Sed (String ricerca,String path,String file){
          String appoggio = null;
          try {
          String comando_sed = Shell.path_unix_utilities+"sed -r -n -e \"s/"+ricerca+"([^0-9])/\\1/p\" "+file;
          // Esegui il comando
          Process pr = Runtime.getRuntime().exec(comando_sed,null,new File(path));
          // Cattura dell' output
          BufferedReader br_in = null;
          try {
               br_in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
               appoggio = br_in.readLine().trim();
               Thread.sleep(100);
               br_in.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_in.close();
          // Cattura dell' errore
          BufferedReader br_err = null;
          try {
          br_err = new BufferedReader(new InputStreamReader(pr.getErrorStream()));
          String buff = null;
          while ((buff = br_err.readLine()) != null) {
          System.out.println("Errore : " + buff);
          Thread.sleep(100);
          br_err.close();
          } catch (IOException ioe) {
          System.out.println("Lista degli errori :");
          ioe.printStackTrace();
          } finally {
          br_err.close();
          catch (Exception ex) {
          System.out.println(ex.getLocalizedMessage());
          return appoggio;
     private static boolean controlloSQLLDR(String path,String file_controllo)     {
          String file_log = replaceAll(file_controllo,".ctl",".log");
          int righe_scartate = 0;
          int righe_rifiutate = 0;
          try     {
               righe_scartate = Integer.parseInt(Shell.eseguiComando_Sed(Shell.string_rifiuto, path, file_log));
               righe_rifiutate = Integer.parseInt(Shell.eseguiComando_Sed(Shell.string_scarto, path, file_log));
          }catch(NumberFormatException nfex)
               System.out.println("\"" +nfex.getMessage() +"\" non è un numero");
          if((righe_scartate == 0) &&(righe_rifiutate == 0)){
               return true;
          else{
               return false;
     private static String replaceAll(String source,String toReplace,String replacement) {
               int idx = source.lastIndexOf( toReplace );
               if ( idx != -1 ) {
               StringBuffer ret = new StringBuffer( source );
               ret.replace( idx, idx+toReplace.length(), replacement );
               while( (idx=source.lastIndexOf(toReplace, idx-1)) != -1 ) {
               ret.replace( idx, idx+toReplace.length(), replacement );
               source = ret.toString();
               return source;
I load it in oracle with the command "loadjava" ...........and it' s ok!
in oracle i create a function and a procedure :
function loader (par1 CHAR,par2 CHAR,par3 IN CHAR,par4 IN CHAR) return boolean
IS LANGUAGE JAVA NAME 'Shell.eseguiSQLLDR(java.lang.String , java.lang.String , java.lang.String , java.lang.String )return boolean';
PROCEDURE PROCEDURA_LOADER AS
BEGIN
DECLARE
PAR1 CHAR(200);
PAR2 CHAR(200);
PAR3 CHAR(200);
PAR4 CHAR(200);
v_Return BOOLEAN;
BEGIN
PAR1 := 'giord/giord';
PAR2 := 'z://cdg/db/txt/cosisan';
PAR3 := 'totati_medico.sh';
PAR4 := 'Medici.ctl';
execute immediate 'CALL DBMS_JAVA.SET_OUTPUT(1000000)';
v_Return := LOADER(PAR1,PAR2,PAR3,PAR4);
END;
END;
the function and the procedure are ok .
i set this permissions in sqlplus :
EXEC dbms_java.grant_permission('GIORD', 'SYS:java.lang.RuntimePermission', 'writeFileDescriptor', '');
EXEC dbms_java.grant_permission('GIORD', 'SYS:java.lang.RuntimePermission', 'readFileDescriptor', '');
EXEC dbms_java.grant_permission('GIORD', 'java.io.FilePermission', '<<ALL FILES>>', 'read ,write, execute,delete',null);
EXEC dbms_java.grant_permission('GIORD','SYS:java.lang.RuntimePermission','*','writeFileDescriptor' );
EXEC dbms_java.grant_permission('GIORD','SYS:java.lang.RuntimePermission','*','readFileDescriptor' );
EXEC dbms_java.grant_permission('GIORD','SYS:java.lang.RuntimePermission','*','executeFileDescriptor' );
EXEC DBMS_JAVA.GRANT_PERMISSION('GIORD', 'SYS:java.lang.RuntimePermission', 'createClassLoader', null);
EXEC DBMS_JAVA.GRANT_PERMISSION('GIORD', 'SYS:java.lang.RuntimePermission', 'setContextClassLoader', null);
EXEC DBMS_JAVA.GRANT_PERMISSION('GIORD', 'SYS:java.lang.RuntimePermission', 'getClassLoader', null);
EXEC DBMS_JAVA.GRANT_PERMISSION('GIORD', 'SYS:java.security.SecurityPermission', 'putProviderProperty.SunJCE', null);
EXEC DBMS_JAVA.GRANT_PERMISSION('GIORD', 'SYS:java.security.SecurityPermission', 'insertProvider.SunJCE', null);
EXEC dbms_java.grant_permission('GIORD','SYS:java.util.PropertyPermission','*','read,write');
EXEC dbms_java.grant_permission('GIORD','SYS:java.net.SocketPermission','*','connect, resolve');
EXEC dbms_java.grant_permission('GIORD', 'SYS:oracle.aurora.security.JServerPermission', 'Debug', null);
and when i run my procedure the result is alwais the same..........Connecting to the database dwh4.
Errore : totati_medico.sh: totati_medico.sh: No such file or directory
Output:
Output: SQL*Loader: Release 10.2.0.1.0 - Production on Lun Set 18 09:11:15 2006
Output:
Output: Copyright (c) 1982, 2005, Oracle. All rights reserved.
Output:
Errore : SQL*Loader-500: Impossibile aprire file (Medici.ctl)
Errore : SQL*Loader-553: file non trovato
Errore : SQL*Loader-509: Errore di sistema: Impossibile trovare il file specificato.
null
"null" non è un numero
Process exited.
Disconnecting from the database dwh4.
WHY ?????
WHY the process is not executed in the path that i want ???
I hope in an answer........and i thanks all

Have you tried fulling qualifying all your paths (both to the control file and SQL*Loader binary).
I read this comment by Steven Feuerstein.
"A similar tip can be found at Calling Java from PL/SQL by Steven Feuerstein (Oracle Magazine, March 2000).
Note: When executing OS commands through this PL/SQL wrapper, Java connects to the OS via a silent login. This means that no environment set-up files are run, and no path is set. Therefore, you must fully qualify the path of the OS commands.
For example, to list the files in the /tmp directory, the following will not work:
SQL> select shellcmd ('ls /tmp') from dual;
However, one of these will work:
SQL> select shellcmd ('/bin/ls /tmp') from dual;
SQL> select shellcmd ('/bin/ksh l /tmp') from dual; "
Here's the link where I found this: http://www.dbonline.cn/source/oracle/20031213before/SQL/Execute%20OS%20Commands%20from%20PLSQL.htm

Books & Tools: Help needed for Begining Java....

Hi,
I am a Computer science Graduate & working. I am new to Java but not Programming. I have some knowledge on OOPS concepts, .Net, Java, C# & web development.
I need Help To pick the Best Book/Books that can make me comfortable in programming Java & Understanding whole Java concept.
I followed many books but found they are not following the Right approach.
I would appreciate if someone can suggest me a Complete Book/Books, which you think have helped.
Thanks.

This is the starter set:
Sun's basic Java tutorial
Sun's New To Java Center. Includes an overview of what Java is, instructions for setting up Java, an intro to programming (that includes links to the above tutorial or to parts of it), quizzes, a list of resources, and info on certification and courses.
http://javaalmanac.com . A couple dozen code examples that supplement The Java Developers Almanac.
jGuru. A general Java resource site. Includes FAQs, forums, courses, more.
JavaRanch. To quote the tagline on their homepage: "a friendly place for Java greenhorns." FAQs, forums (moderated, I believe), sample code, all kinds of goodies for newbies. From what I've heard, they live up to the "friendly" claim.
Bruce Eckel's Thinking in Java (Available online.)
Joshua Bloch's Effective Java
Bert Bates and Kathy Sierra's Head First Java.
James Gosling's The Java Programming Language. Gosling is
the creator of Java. It doesn't get much more authoritative than this.

What do %W% %E% mean in the beginning Java comment?

I was wondering if anyone knew what the purpose of %W% and %E% at the top of the file comments means. Can't seem to find it anywhere.
From the Java Code Conventions document at:
11.1 Java Source File Example
The following example shows how to format a Java source file containing a single public class.
Interfaces are formatted similarly. For more information, see ?Class and Interface
Declarations? on page 4 and ?Documentation Comments? on page 9
* %W% %E% Firstname Lastname
* Copyright (c) 1993-1996 Sun Microsystems, Inc. All Rights Reserved.
* This software is the confidential and proprietary information of Sun
* Microsystems, Inc. ("Confidential Information"). You shall not
* disclose such Confidential Information and shall use it only in
* accordance with the terms of the license agreement you entered into
* with Sun.
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/

It doesn't mean anything in the context of Java and comments, but some version managers might substitute that with information that is retrieved at check-in time.
Kaj

How to begin Java EE with plan?

Excuse me, I am a beginner.
Why are variances in architectures of Java EE?
If the differences depends on the different purposes.
May I set up in simple environment of Java EE initially, then
to augment it such as to modify or change the parameter of
InitialContexts,(JNDI)
http://carbon.sourceforge.net/modules/jndi/docs/InitialContextFactoryUsage.html ?
Thank you a lot!

Hi Fernand,
Hope below link will be useful for you.
Re: WEBAS 7.10 How to undeploy with JSPM
Cheers.....,
Raghu

Beginning java programming in a course from home

hi, i've recently started working on a java course, learning from home and am a bit stuck on what it all means really as my level of english isnt very good.
it says i have to write a class to represent a calendar date, and then write a program that instantiates 2 of these date objects, initializes their member variables and print them out.
Would someone please be abel to help me with an example of this,
I would be so grateful!!!
from
waynemorgan86

not compiled... not unit tested... but commented to the beejeepers.
//DateStringExample is an example of a simple java class. It creates two dates,
//initialises their member variables, and prints both values.
class DateStringExample
     //the DateString class encapsulates all the variables and methods which
     //enable is to store a date as a String, and retrieve it again.
     private String DateString {
          //a "member" variable... note that it is private meaning that it is
          //visible only within the DateString class... so other classes can't
          //see it, allowing you to restrict access to this value, and validate
          //value when it is "stored".
          private String date;
          //a default contructor ("no arg" constructor) nb: if you don't
          //specify a default contructor java creates an empty one for you.
          DateString() {
               //set the value of the date variable in this instance of the DateString
               //class to todays date, which is the default value of a Date object.
               this.date = (new Date).toString;
          //a "setter contructor" allows you to create a new DateString and
          //set it's value in one easy move.
          DateString(String date) throws Exception {
               setDate(date);
          //a "setter" validates the supplied value and sets the member variable.
          void setDate(String date) throws Exception {
               if (date = null) throw Exception("null date");
               try {
                    Date tmp = DateFormat.parse(date);
               } catch ( ParseException e ) {
                    throw new Exception("invalid date " + date, e);
               this.date = date;
          //a "getter" returns the current value of the member variable.
          DateString getDate() {
               return(this.date);
     //this is the special main method which java run's automatically when
     //you run the "program"
     public static void main(String[] argv)
          try {
               //get me an instance of a DateString called today, which contains
               //todays date (as a string);
               DateString today = new DateString();
               //get me another instance of a DateString called today, which contains
               //tomorrowsa date
               DateString tomorrow = new DateString("2006-09-20 12:46:00");
               //output the two values
               System.out.println("today is "+today+" and tomorrow is "+tomorrow);
               //try to set tommorow to an invalid date, and print again
               tomorrow.setDate("2006-02-31 00:00:00");
               System.out.println("today is "+today+" and tomorrow is "+tomorrow);
          //catch any errors, and just report them to the standard error stream.
          } catch (Exception e) {
               System.err.println(e);
//NOTES:
//* This whole class is obviously a complete waste of time, except as
//      a simple example of a class to newbie java programmers.
//* The Java language provides a rich featured set of classes for date manipulation.//and a few obvious bugs... hand this in as is and you will fail.
corlettk: removed dodgy BadDateStringException, I think.

Beginning java - extension documentation issue

Hi
I'm a java beginner. I have installed an extension on my system (mysql-connector-java-5.0.4-bin.jar) which seems to work fine. I'm using eclipse for development.
If I look in system library I can find the relevant mysql stuff. I would like to take a closer look att the class ResultSet class found in mysql-connector. When i double click on it am told "source not found". I have tried changing attached source to no avail.
Since I'm new at this I'm not quite sure if I actually need to download any source or if this is just a path issue.
I would appreciate any help pointing me in the right direction.
Thanks

Hi
The source files appear to be included as a separate folder in the download bundle, available from here:
http://dev.mysql.com/get/Downloads/Connector-J/mysql-connector-java-5.0.4.tar.gz /from/pick#mirrors
Pick a download mirror, then unzip/untar the download and you'll find a folder called src. The sources should be in there. You don't need the sources to be available if you have the jar file, but it can sometimes be useful to have them.
Bob

Beginning Java help needed.

I'm trying to write a program that would display the elapsed time after double clicking in seconds. For instance, first click will start the timer, but it will not display the elapse time after the second click. Here is my code.
public class ClickTimer extends WindowController {
private double startingTime;
private Text message;
public ClickTimer () {startController (700,500);
public void begin() {
message = new Text( "Double click twice to display time elapse." ,50, 50
,canvas );
public void onMousePress(Location point) {
startingTime = System.currentTimeMillis();
if (point.getclickCount() == 2) {float elapsedTimeSec = elapsedTimeMillis/1000F;
}}

For instance, first click will start the timer, but it will not display the elapse time after the second click.Since there's no code there that would display elapsed time, that isn't surprising.
Your onMousePress method always sets the startTime value (no matter what click it is), which is probably not what you want.
Text? Location? WindowController? What library are you using? You should say up front.

Begining Java programmer

If someone could help me. I have two classes that extend the Panel class.
I need to be able to put the two panels into one frame. I am stummed as to how to do this. I can get one or the other, but not both.
Any help would be great

This depend on the LayoutManager used.
MyPanelA panelA=new MyPanelA(); //your extended Panel
MyPanelB panelB=new MyPanelB(); //your extended Panel
// set the layout to be used for the frame
myFrame.setLayout(new BorderLayout());
// add the first panel on North of frame
myFrame.getContentPane().add(panelA,Border.NORTH);
// add the first panel on South of frame
myFrame.getContentPane().add(panelB,BORDER.SOUTH);There's maybe some erros as i've done that from memory.
Check this tutorial about LayoutManager:
http://java.sun.com/docs/books/tutorial/uiswing/mini/layout.html
Hope this helps.

Begin audio part way into presentation

I want to begin music in a presentation about half-way through rather than at the beginning. Is that possible?

Greetings and welcome to the Forum:
This topic has been addressed in numerous previous threads in the Forum. Try searching on the keywords music, hyperlink, soundtrack, etc.
Briefly, if you want to begin a music track that will carry through several slides, it must be created as a Soundtrack for a presentation that encompasses those slides. If these slides are a subset of a larger presentation, then you need to create separate sub-presentations, each containing the particular group of slides. Each then can have its own soundtrack. Finally, you will have to link the presentations together via Hyperlinks.
If you want a music track to play through only one slide, that is easy: Just drag the file icon for the music track into the slide; select it and the assign it to Start Audio in the Build-In menu. Be aware, however, that the track will stop playing as soon as you progress to the next slide.
So, a quick answer to your question is "maybe" but it depends on how you want to structure your presentation.
Good luck.

Beginning java part 2

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