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servlet programmer beginner

Posted on 2004-10-25
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Last Modified: 2013-11-24
hi ,

I am new to servlet programming. I have downloaded latest versions of Apache and Tomcat on my Windows NT machine.

I have written my first servlet program. Now i am confused where to save it. Do i compile it using javac "filename" and run it using java "filename" (like we do for usal java programs)

Any advice greatly appreciated.

This is my simple servlet program :

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class Servlet1 extends HttpServlet
{
public void doGet(HttpServletRequest request, HttpServletResponce responce) throws ServletException, IOException
{
PrintWriter out = responce.getWriter();
out.println("Helloooooooooo World");
}
}

thanks,
J
0
Question by:jaggernat
    40 Comments
     
    LVL 8

    Expert Comment

    by:kiranhk
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    0
     

    Expert Comment

    by:Emilda
    http://jakarta.apache.org/tomcat/tomcat-4.0-doc/appdev/deployment.html

    The above link gives you information on how to deploy your application into Tomcat.

    You need to compile above program using javac and put your class file under the folder /WEB-INF/classes/ .

    you can use the existing directory $CATALINA_HOME/webapps/ROOT/WEB-INF/classes to put your servlet classes. In this case you can access your servlet by invoking http://hostname:8080/servlet/Servlet1

    Good practise is to make a dirctory under webapps and put all your servlets under WEB-INF/classes underneath that directory
    eg : $CATALINA_HOME/webapps/myroot/WEB-INF/classes

    In this case you can access your classes by : http://hostname:8080/myrrot/servlet/Servlet1

    Also read:  http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/Servlets.html

    Hope this helps.
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    For some reason, i cant start the server .
     
    Detailed Description:

    My Tomcat is stored in this following directory:
    c:\program files\Apache Group\Tomcat 4.1

    Under tomcat 4.1  directory  , i made a directory  called  "ap1"(which i created to store applications) ,under "ap1" directory i created  "Web-inf" directory , and under "Web-inf directory" i created  the "classes" directory.

    I have stored my first java program "servlet1.java" in the "classes" directory .

    In the  environment variables , i have set some thing like this
    set JAVA_HOME=c:\j2sdk1.4.2_06;  set CATALINA_HOME=c:\Program Files\Apache Group\Tomcat 4.1

    when i run the command "startup" from c:\program files\Apache Group\Tomcat 4.1\bin
    the server starts , but terminates in between and throws an error message (like file not found).

    Also , i cant run the javac command from the command prompt.

    ...........This is getting real frustrating..

    Any advice greatly appreciated.

    thanks,
    J

    0
     

    Expert Comment

    by:Emilda
    you need to create "api" directory under c:\program files\Apache Group\Tomcat 4.1\webapps and not under c:\program files\Apache Group\Tomcat 4.1  and WEB-INF is case sensitive.

    You need to solve the problem with tomcat startup. Try to find more details of the error. Since you cannot even compile java program from command prompt, that could be the root of the problem. Try to figure out why you are not able to run javac. Try running "echo %JAVA_HOME%" to see if the env variable is set correctly. You need to set PATH variable as well.

    set PATH = %PATH%;%JAVA_HOME%\bin
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ok when i run "startup" it says "Catalina_Home is not defined correctly. This environment variable is needed to run this  program .

    Do i need to define "CATALINA_HOME" in environment variable??

    thanks,
    J
    0
     

    Expert Comment

    by:Emilda
    Yes, you need to set CATALINA_HOME, JAVA_HOME and PATH in the environment variable.
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ok ..JAVA_HOME and PATH environment variables are set..  How do i set CATALINE_HOME variable ?

    thanks,
    J

    0
     

    Expert Comment

    by:Emilda
    In the same way you can set CATALINE_HOME, give it the value :

    Right click "My Computer" icon on the desktop and select "Properties" click "Advanced" tab and select "Environment Variables", click "new" button under user variables,
    Give name as: CATALINE_HOME
    value as: c:\Program Files\Apache Group\Tomcat 4.1

    Don't set environment variable in the command prompt giving the set option, that's only temporary.

    0
     
    LVL 10

    Author Comment

    by:jaggernat
    i dont know....i am still getting the same error.."Catalina_Home is not defined correctly"

    couple of hours back i deleted one line of code from startup.bat or catalina.bat (dont remember exactly). I think thats the problem.

    will i have to uninstall and reinstall Tomcat.

    thanks,
    sorry for the trouble.

    this question s is definetely worth more than 150 points :)


    0
     

    Expert Comment

    by:Emilda
    Given below is the contents of startup.bat, may be from that you can figure out which line you deleted.
    =======================================================
    @echo off
    if "%OS%" == "Windows_NT" setlocal
    rem ---------------------------------------------------------------------------
    rem Start script for the CATALINA Server
    rem
    rem $Id: startup.bat,v 1.4 2002/08/04 18:19:43 patrickl Exp $
    rem ---------------------------------------------------------------------------

    rem Guess CATALINA_HOME if not defined
    if not "%CATALINA_HOME%" == "" goto gotHome
    set CATALINA_HOME=.
    if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
    set CATALINA_HOME=..
    :gotHome
    if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
    echo The CATALINA_HOME environment variable is not defined correctly
    echo This environment variable is needed to run this program
    goto end
    :okHome

    set EXECUTABLE=%CATALINA_HOME%\bin\catalina.bat

    rem Check that target executable exists
    if exist "%EXECUTABLE%" goto okExec
    echo Cannot find %EXECUTABLE%
    echo This file is needed to run this program
    goto end
    :okExec

    rem Get remaining unshifted command line arguments and save them in the
    set CMD_LINE_ARGS=
    :setArgs
    if ""%1""=="""" goto doneSetArgs
    set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
    shift
    goto setArgs
    :doneSetArgs

    call "%EXECUTABLE%" start %CMD_LINE_ARGS%

    :end
    =========================================================
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    can you paste catalina.bat too. it may have been from that file.

    thanks,
    J
    0
     

    Expert Comment

    by:Emilda
    @echo off
    if "%OS%" == "Windows_NT" setlocal
    rem ---------------------------------------------------------------------------
    rem Start/Stop Script for the CATALINA Server
    rem
    rem Environment Variable Prequisites
    rem
    rem   CATALINA_HOME   May point at your Catalina "build" directory.
    rem
    rem   CATALINA_BASE   (Optional) Base directory for resolving dynamic portions
    rem                   of a Catalina installation.  If not present, resolves to
    rem                   the same directory that CATALINA_HOME points to.
    rem
    rem   CATALINA_OPTS   (Optional) Java runtime options used when the "start",
    rem                   "stop", or "run" command is executed.
    rem
    rem   CATALINA_TMPDIR (Optional) Directory path location of temporary directory
    rem                   the JVM should use (java.io.tmpdir).  Defaults to
    rem                   %CATALINA_BASE%\temp.
    rem
    rem   JAVA_HOME       Must point at your Java Development Kit installation.
    rem
    rem   JAVA_OPTS       (Optional) Java runtime options used when the "start",
    rem                   "stop", or "run" command is executed.
    rem
    rem   JSSE_HOME       (Optional) May point at your Java Secure Sockets Extension
    rem                   (JSSE) installation, whose JAR files will be added to the
    rem                   system class path used to start Tomcat.
    rem
    rem   JPDA_TRANSPORT  (Optional) JPDA transport used when the "jpda start"
    rem                   command is executed. The default is "dt_shmem".
    rem
    rem   JPDA_ADDRESS    (Optional) Java runtime options used when the "jpda start"
    rem                   command is executed. The default is "jdbconn".
    rem
    rem $Id: catalina.bat,v 1.7 2003/11/05 11:40:18 remm Exp $
    rem ---------------------------------------------------------------------------

    rem Guess CATALINA_HOME if not defined
    if not "%CATALINA_HOME%" == "" goto gotHome
    set CATALINA_HOME=.
    if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
    set CATALINA_HOME=..
    :gotHome
    if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
    echo The CATALINA_HOME environment variable is not defined correctly
    echo This environment variable is needed to run this program
    goto end
    :okHome

    rem Get standard environment variables
    if exist "%CATALINA_HOME%\bin\setenv.bat" call "%CATALINA_HOME%\bin\setenv.bat"

    rem Get standard Java environment variables
    if exist "%CATALINA_HOME%\bin\setclasspath.bat" goto okSetclasspath
    echo Cannot find %CATALINA_HOME%\bin\setclasspath.bat
    echo This file is needed to run this program
    goto end
    :okSetclasspath
    set BASEDIR=%CATALINA_HOME%
    call "%CATALINA_HOME%\bin\setclasspath.bat"

    rem Add on extra jar files to CLASSPATH
    if "%JSSE_HOME%" == "" goto noJsse
    set CLASSPATH=%CLASSPATH%;%JSSE_HOME%\lib\jcert.jar;%JSSE_HOME%\lib\jnet.jar;%JSSE_HOME%\lib\jsse.jar
    :noJsse
    set CLASSPATH=%CLASSPATH%;%CATALINA_HOME%\bin\bootstrap.jar

    if not "%CATALINA_BASE%" == "" goto gotBase
    set CATALINA_BASE=%CATALINA_HOME%
    :gotBase

    if not "%CATALINA_TMPDIR%" == "" goto gotTmpdir
    set CATALINA_TMPDIR=%CATALINA_BASE%\temp
    :gotTmpdir

    rem ----- Execute The Requested Command ---------------------------------------

    echo Using CATALINA_BASE:   %CATALINA_BASE%
    echo Using CATALINA_HOME:   %CATALINA_HOME%
    echo Using CATALINA_TMPDIR: %CATALINA_TMPDIR%
    echo Using JAVA_HOME:       %JAVA_HOME%

    set _EXECJAVA=%_RUNJAVA%
    set MAINCLASS=org.apache.catalina.startup.Bootstrap
    set ACTION=start
    set SECURITY_POLICY_FILE=
    set DEBUG_OPTS=
    set JPDA=

    if not ""%1"" == ""jpda"" goto noJpda
    set JPDA=jpda
    if not "%JPDA_TRANSPORT%" == "" goto gotJpdaTransport
    set JPDA_TRANSPORT=dt_shmem
    :gotJpdaTransport
    if not "%JPDA_ADDRESS%" == "" goto gotJpdaAddress
    set JPDA_ADDRESS=jdbconn
    :gotJpdaAddress
    shift
    :noJpda

    if ""%1"" == ""debug"" goto doDebug
    if ""%1"" == ""run"" goto doRun
    if ""%1"" == ""start"" goto doStart
    if ""%1"" == ""stop"" goto doStop

    echo Usage:  catalina ( commands ... )
    echo commands:
    echo   debug             Start Catalina in a debugger
    echo   debug -security   Debug Catalina with a security manager
    echo   jpda start        Start Catalina under JPDA debugger
    echo   run               Start Catalina in the current window
    echo   run -security     Start in the current window with security manager
    echo   start             Start Catalina in a separate window
    echo   start -security   Start in a separate window with security manager
    echo   stop              Stop Catalina
    goto end

    :doDebug
    shift
    set _EXECJAVA=%_RUNJDB%
    set DEBUG_OPTS=-sourcepath "%CATALINA_HOME%\..\..\jakarta-tomcat-catalina\catalina\src\share"
    if not ""%1"" == ""-security"" goto execCmd
    shift
    echo Using Security Manager
    set SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy
    goto execCmd

    :doRun
    shift
    if not ""%1"" == ""-security"" goto execCmd
    shift
    echo Using Security Manager
    set SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy
    goto execCmd

    :doStart
    shift
    if not "%OS%" == "Windows_NT" goto noTitle
    set _EXECJAVA=start "Tomcat" %_RUNJAVA%
    goto gotTitle
    :noTitle
    set _EXECJAVA=start %_RUNJAVA%
    :gotTitle
    if not ""%1"" == ""-security"" goto execCmd
    shift
    echo Using Security Manager
    set SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy
    goto execCmd

    :doStop
    shift
    set ACTION=stop
    goto execCmd

    :execCmd
    rem Get remaining unshifted command line arguments and save them in the
    set CMD_LINE_ARGS=
    :setArgs
    if ""%1""=="""" goto doneSetArgs
    set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
    shift
    goto setArgs
    :doneSetArgs

    rem Execute Java with the applicable properties
    if not "%JPDA%" == "" goto doJpda
    if not "%SECURITY_POLICY_FILE%" == "" goto doSecurity
    %_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
    goto end
    :doSecurity
    %_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
    goto end
    :doJpda
    if not "%SECURITY_POLICY_FILE%" == "" goto doSecurityJpda
    %_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% -Xdebug -Xrunjdwp:transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=n %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
    goto end
    :doSecurityJpda
    %_EXECJAVA% %JAVA_OPTS% %CATALINA_OPTS% -Xrunjdwp:transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=n %DEBUG_OPTS% -Djava.endorsed.dirs="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
    goto end

    :end
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ok ..  here is the problem.

    when the server starts , it pops up the error message ' Windows cannot find : "-Dsun.io.canoncaches=false" ' .

    i searched for "-Dsun.io.canoncaches=false" , and found that it is a line of code in "catalina.bat".

    These are all the environment variables i have :

    variable                                           value

    CATALINA_HOME                       set CATALINA_HOME=C:\Program Files\Apache Group\Tomcat 4.1\bin
    JAVA_HOME                              set JAVA_HOME=C:\j2sdk1.4.2_06\bin
    PATH                                        PATH=%PATH%c:\j2sdk1.4.2_06\bin;%CATALINA_HOME%\bin

    could you please help me out..

    thanks,
    J
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    your environment variables should be

    CATALINA_HOME                       set CATALINA_HOME=C:\Program Files\Apache Group\Tomcat 4.1
    JAVA_HOME                              set JAVA_HOME=C:\j2sdk1.4.2_06

    dont add the bin directory in your CATALINA_HOME and JAVA_HOME variables
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    it  still   says "catalina_home " variable is not defined correctly .


    thanks,
    J

    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    try this
    set CATALINA_HOME=C:\Progra~1\Apache Group\Tomcat 4.1
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    try this
    set CATALINA_HOME=C:\Progra~1\Apache~1\Tomcat 4.1

    0
     
    LVL 86

    Expert Comment

    by:CEHJ
    >>it  still   says "catalina_home " variable is not defined correctly .

    It will, as it should not contain spaces. Use

    set CATALINA_HOME="C:\Program Files\Apache Group\Tomcat 4.1"


    0
     
    LVL 10

    Author Comment

    by:jaggernat
    no difference ,,doesnt work  

    when set to :
    set CATALINA_HOME=C:\Progra~1\Apache~1\Tomcat 4.1

    it says --.>"catalina_home " variable is not defined correctly

    and

    when set to:
    set CATALINA_HOME="C:\Program Files\Apache Group\Tomcat 4.1"

    it says --> File\Apache  was unexpected at this time.


    thanks,
    J



    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    Add these lines in your startup.bat after this line rem Guess CATALINA_HOME if not defined
    set JAVA_HOME=C:\j2sdk1.4.2_06
    set CATALINA_HOME=C:\Progra~1\Apache~1\Tomcat 4.1
    0
     
    LVL 86

    Expert Comment

    by:CEHJ
    Personally i'd set those environment variables through Windows itself. Go

    Start|Help

    and look up 'environment variable' for your version of Windows
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ok ..i did the following steps :
    <<<<<
    Add these lines in your startup.bat after this line rem Guess CATALINA_HOME if not defined
    set JAVA_HOME=C:\j2sdk1.4.2_06
    set CATALINA_HOME=C:\Progra~1\Apache~1\Tomcat 4.1
    >>>>>>

    now i dont get any error messages ...Now it opens an other window with the label Tomcat and quickly dissapears...

    looks like we are getting close..

    thanks,
    J


    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    ok, good.
    now go to startup.bat and change this line
    call "%EXECUTABLE%" start %CMD_LINE_ARGS%

    to
    call "%EXECUTABLE%" run %CMD_LINE_ARGS%


    then you can post whatever error you r getting here
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ther are a whole bunch of errors ..it starts with

    java.net.bind exception :address already in use JVM_BINDPOINT:80
    at org.apache.tomcat.util.net.poolTCPendpoint.InitendPoint(poolTCPendpoint.java)

    and goes on and on

     
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    that means your port 80 is already being used by a different address. you need to change this port number to different one or you need to shutdown the process which is using port 80 and then start your tomcat.

    go to tomcat->conf folder and change the port number located in server.xml change the port number to 10110 or any number greater than 5000 and then restart your tomcat. otherwise you can post your server.xml here

        <!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
        <Connector port="8080"
                   maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
                   enableLookups="false" redirectPort="8443" acceptCount="100"
                   debug="0" connectionTimeout="20000"
                   disableUploadTimeout="true" />
        <!-- Note : To disable connection timeouts, set connectionTimeout value
         to 0 -->
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    ok
    Now, which port number should be changed with 10110.

     there is
     server port = 8005 shutdown=SHUTDOWN  debug=0

    there is port 8009
    there is port 8002 ..

    ect..

    thanks,
    J


    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    i have posted the lines where u need to change. dont change anything other than what i have posted in my previous comment. after you change the port while accessing the server you need to use http://localhost:10110

    just go to the line  
       <!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
    <Connector port="8080"

    in your server.xml and then change the port number as specified
    0
     
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    Author Comment

    by:jaggernat
    ok ,,,,in my server.xml ,there is not port with the number "8080".. there is 8081, 8443, 8082,8083,,ect.

    The only instance where 8080 is mentioned is this:
    by default a non-ssl/1.1 connector is established on port 8080. You can also enable
    non-ssl/1.1 connector on port 8443.........

    thanks,
    J


    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    ok, fine. but do u have the lines which i am mentioning. just change whatever port number is there and restart.

    just go to the line  
       <!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
    <Connector port="xxxxx"

    in your server.xml and then change the port number as specified


    or better still post your full server.xml here
    0
     
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    Author Comment

    by:jaggernat
    ok ...is it possible for me to copy paste the server.xml code
    I am looking at server.xml from the dos prompt->edit mode..
    I guess copy -paste doesnt work..is there any other way..

    thanks,
    J
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    there is a menu option for copy. first select all the lines or the lines which i have mentioned and then go to Edit->Copy.
    0
     
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    Author Comment

    by:jaggernat
    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    ok, atleast can you see and type the lines which i am telling
    0
     
    LVL 10

    Author Comment

    by:jaggernat
    I DO NOT HAVE

     <!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
    <Connector port="xxxxx"

    THERE IS

    <define a non-ssl coyote HTTP/1.1 Connector on port 8081 >
    connector class name = "org.apache.coyote.tomcat4.coyoteconnector" port ="80"
    minprocessors=5...ect

    and there is

     <!-- Define a non-SSL HTTP/1.1 Connector on port 8443 -->
    <port="8443"

    ...everything but 8080 is missing ...



    0
     
    LVL 8

    Expert Comment

    by:kiranhk
    ok, good. now change the line
    connector class name = "org.apache.coyote.tomcat4.coyoteconnector" port ="80"
    to some other port number and start the tomcat. Access your server as i have told before using the port number which u give here

    this should work now!!!!!!!!!!!!!!!!!!!!!!!!!
    0
     
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    Author Comment

    by:jaggernat
    excellent ..thanks...
    0
     
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    Author Comment

    by:jaggernat
    one last question...
    where do i save the java servelt files ....and where should i run javac from....

    thanks,
    J
    0
     
    LVL 8

    Accepted Solution

    by:
    Please close the question in the Java Programming Topic area

    Do a search for Javac.exe

    If I do a search on MY COMPUTER I find this
    C:\jdk1.3.1_02\bin\javac.exe

    so I could
    a) type C:\jdk1.3.1_02\bin\javac.exe to run javac.exe
    or
    b)set path=%path%;C:\jdk1.3.1_02\bin
    then I can type javac in any directory C:\mycomputer c:\winnt etc.

    as far as
    set classpath=%classpath%;
    Do a search for *.jar, whatever dir comes up, add to this variable as well.

    Then run javac in whichever dir you .java files reside.

    This can be done also by clicking START>CONTROL PANEL>SYSTEM>ADVANCED>ENV VARIABLE. This only needs to be done once here.


    http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_21179277.html

    http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_21177639.html
    0
     
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    Author Comment

    by:jaggernat
    thanks kiranhk.
    0

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    INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
    Viewers learn about the scanner class in this video and are introduced to receiving user input for their programs. Additionally, objects, conditional statements, and loops are used to help reinforce the concepts. Introduce Scanner class: Importing…
    The viewer will learn how to implement Singleton Design Pattern in Java.

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