Javac command

I'm having trouble compiling my programs. Everytime I try to compile, it says it's not a recognised command. Does anyone know which enviroment variable has to be set to the path of my java installation?

Yes, add %JAVA_HOME%\bin to your PATH, where JAVA_HOME is the directory to which Java is installed.
If you already have it set, then you installed the JRE and not the JDK. Make sure you have a JAVA_HOME\bin directory, and that you can see javac.exe, java.exe, jar.exe, etc.
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Similar Messages

I'm new to Java and can't get javac command working

Ok first of all hello ( i'm new to the forum ), second i'm reading a book about Java and im trying to compile a sample code from the book, but javac command gained life and it's against me. So the book i'm reading is Sams Teach Yourself Java in 21 Days (YAY), and the code i want to compile is an application that works with another bit of code that mimics what a robot could do inside a volcano. So the Volcano program code is the following ( i'll post the robot code at the end of the post):
1: class VolcanoApp {
2: public static void main(String[] arguments) {
3: VolcanoRobot dante = new VolcanoRobot();
4: dante.status = ?exploring?;
5: dante.speed = 2;
6: dante.temperature = 510;
7:
8: dante.showAttributes();
9: System.out.println(?Increasing speed to 3.?);
10: dante.speed = 3;
11: dante.showAttributes();
12: System.out.println(?Changing temperature to 670.?);
13: dante.temperature = 670;
14: dante.showAttributes();
15: System.out.println(?Checking the temperature.?);
16: dante.checkTemperature();
17: dante.showAttributes();
18: }
19: }
Ignore the numbers they are used for explaining stuff in the book, and i din't copy the indentation.
So what i do is that i creat a file with notepad ( no fancy stuff only plain old notepad ) and i copy this code, remove the numbers and make the indents.
After that i save as .txt file with the apropriate name ( i know it's case sensitive ). After that i open command prompt and write:
javac VolcanoApp.java
And it tells me that "javac is not recognized as an internal or external command operable program or batch file".
I managed to solve that by going to the control panel and by adding to the system variables for my user in the path variable this :
;C:\JAVAJDK\bin
( C:\JAVAJDK is where JDK is installed)
And then i modified the system variables like this:
In the CLASSPATH i entered this .;%JAVA_HOME%\lib\tools.jar
In JAVA_HOME i entered this C:\JAVAJDK
Setting the variables like this made the javac error go away but now when i write in command line
javac VolcanoApp.java
It gives me this error
javac: file not found : VolcanoApp.java
Usage: javac options source files
use -help for a list of possible options
And then i read that i can drop my java file directly in the javac file. So i did.
When i drop my VolcanoApp.java in the javac file it open a command line window and writes a bunch of stuff in like a milisecond and shuts down. And no file is created.
I wanted to know what was writen in that window so i did it again and took a print screen and pasted it on paint ( it writed so much text that i only got a little bit but enough to see what hapend)
I read it and in the print screen it said it had 15 errors ( so far ) and then it point the errors with little arrows and there were characters that weren't present in the original code.
What hapend the compiler added wierd letters?
SO, my real question is, how the heck do i get javac working and compiling stuff properly?
Plz help i'm getting mad at this! ; (
And the code for the "robot":
1: class VolcanoRobot {
2: String status;
3: int speed;
4: float temperature;
5:
6: void checkTemperature() {
7: if (temperature > 660) {
8: status = ?returning home?;
9: speed = 5;
10: }
11: }
12:
13: void showAttributes() {
14: System.out.println(?Status: ? + status);
15: System.out.println(?Speed: ? + speed);
16: System.out.println(?Temperature: ? + temperature);
17: }
18: }
Again no indents and ignore the numbers. In the book it only said to compile the VolcanoApp.java , and not the VolcanoRobot.java
Edit:
I'm using Windows Vista Home Premium 32 bit.
Edited by: BBlop on Dec 13, 2009 11:29 AM

guess what it says java file. So yes i'm sure. Sarcasm. Not the best way to encourage a total stranger to help you. Then there's
Sorry if i wasn't more clear but was that response needed?No it wasn't needed, but I'm not the one asking for help so I have the luxury of not worrying too much about it. It's extremely frustrating trying to drag relevant information out of someone, and makes one less inclined to bother.
Anyways, there's still nothing in this thread that actually explicitly says "there is a file called VolcanoApp.java in the directory where I'm running javac from" and I really can't be bothered banging my head against the wall any longer. You've made a silly mistake, or a false assumption. We all do it from time to time. My advice is, take a break, go for a walk and re-visit this in a while. You'll probably spot the mistake right away.

How can i run javac command in a Servlet?

I wanna use javac command in a Servlet ,
but it can not load the tomcat's lib.
What can i do?

Try out. But Iam not sure.
Runtime.getRuntime("Cmd.Exe"). This wiil open the dos prompt.
Create ouput stream and write in to it.Try to execute key.
To invoke the enter key , use ascii value of the enter key

Javac command not found

I am new to Java programming and I wrote my first program to say "Hello World!" ...what a surprise... anyway, when I try to compile it, my command promt does not recognize the 'javac' command. I bought a book on Java that came with the J2SE Development Kit AND SDK, and they are installed to the folder it asked for, however my computer still will not recognize it... Any thoughts???
P.S. Thanks ahead of time for any solutions... My goal is to develop a 'graphic equalizer' my March 17, 2006 - the opening of my school's musical AIDA! It seems like a far goal for a beginner, but I'm a fast learner and hope to develop one for use by our sound tech...

Hi..
I just installed my Java SDK&RE (1.4.2.06) and put the BIN filder in the path variable and now the compilig works but I'm getting the same message when trying to start run the "hello world" program: "Exception in thread "main" java.lang.noclassdeffounderror: Hello".
I tried your "-cp ." method and it works perfectly, but I KNOW that last time I had Java installed I didn't have to use that option.. I know I'm forgeting something I just can'[t remember what :)
It's been a year since I used Java and I'm trying to get back in the game now.. and this fundamental error is driving me crazy.
I have an idea of what could cause this error.. I MOVED the entire "C:\j2sdk1.4.2_06" folder to some other location...actually I INTALLED it to some other location and I'm thinking this could be the cause..
also, I'm looking at the WinXP Enviroment Variables and my Java installation put here another variable CLASSPATH with value: "C:\Program Files\Java\jre1.5.0_01\lib\ext\QTJava.zip". So I think I 'll try putting another CLASSPATH here and see what happens..
anyway, any ideas?
thanks in advance

Javac command doesn't work

i have installed jdk1.5.0_04 in /usr/java/ in Linux OS,and set the environment variable in /etc/profile.
But when i compile java file, #javac, it output error msg:
libgcj-java-placeholder.sh
This script is a placeholder for the /usr/bin/java and /usr/bin/javac
master links required by jpackage.org conventions. libgcj's
rmiregistry, rmic and jar tools are now slave symlinks to these
masters, and are managed by the alternatives(8) system.
This change was necessary because the rmiregistry, rmic and jar tools
installed by previous versions of libgcj conflicted with symlinks
installed by jpackage.org JVM packages.
Everything seems right as following:
When i #echo $PATH, it reads
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/usr/java/jdk1.5.0_04/bin:/root/bin
#java -version
java version "1.5.0_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_04-b05)
Java HotSpot(TM) Client VM (build 1.5.0_04-b05, mixed mode, sharing)
#java, it reads the list of the usage
yet i can not run the javac command, what's wrong with that, i am so confused. any help would be appreciated, thank you!

Take a look at this reply on a different thread:
http://forum.java.sun.com/thread.jspa?threadID=685889

Syntax for javac command line in DOS

Can anyone help me with the proper syntax fror the javac command line? Based on the Java Tutorial, I type the following line while in: C:\Program Files\Java>
c:\progra~1\java\bin\javac hellow~1.jav
This returns the following error message:
javac: invalid flag: hellow~1.jav
Usage: javac <options> <source files>
where possible options include:
-g Generate all debugging info
-g:none Generate no debugging info
-g:{lines,vars,source} Generate only some debugging info
Rest deleted, you get the drift. A long time has passed since I have used DOS, but I thought that options were just that; they were not essential to run a program. If they are necessary, how do you set an option? for example, I have tried the command:
C:\Program Files\Java>c:\progra~1\java\bin\javac -g hellow~1
which gives me the following error:
javac: invalid flag: hellow~1
I would really appreciate any suggestions anyone out there has for solving this apparently simple & stupid problem.

Many thanks for these suggestions. I finally got javac to work by putting the file name HelloWorldApp.java inside of quote marks (i.e. "HelloWorldApp.java"). The program compiled the file, & I now have a HelloWorldApp.class file in my java directory. Unfortunately, I am now having trouble with the next tutorial step: getting java to use the file.
I am discovering there are some very strange things about DOS since the last time I used it. For example, the cd command recognizes either cd c:\progra~1\java OR c:\"Program Files"\java. If the quote marks are omitted a "file not found" error is returned. There seems to be some sort of problem with ways that long file names are dealt with in DOS. I notice that many contribs to this list enter long file names or directories without quote marks; indeed, this is standard format in the java tutorial. This is probably a really dumb question, but is there someway to tell DOS to recognize long names without quote marks?
Once again, thanks for the help.

Javac command in windows command prompt

Hi, i would just like to know how i can enable the javac command in the command prompt of windows without being in the java/bin directory...i have tried env. variables and stuff but to no avail, however the java command work.
Thanks Rudy
ps does anyone know any good rmi tutorials which are easy to follow, thanks.

Err, nm, just reread that.
The environment Path is the way to go.
Just add the bin directory to the end of the PATH in the advanced option of my computer. You may need to reboot.

Using the javac command

I'm trying to create a class with the javac command. I used notepad to write the code and saved the file as .java, but when I try to use the javac command to compile it I'm told that it can't read the file. Not sure what the problem is. Any help is appreciated. Thanks.
- rob

Notepad will try to save any file with .txt as the extension. In the Save As dialog, even if you type factorial.java, Notepad might save the file as factorial.java.txt. If you look at the file in a Windows folder, it might display as factorial.java. To find out if this is your problem, use the DIR command in a DOS console to display the actual file name. If this is the problem you can (1) put double quotes around the file name in the Save As dialog, "factorial.java" or (2) make .java a text file type for your system.

Using javac command

I have created desktop gui application and I see several files created. I want to compile from the using the javac command. But I do not know which of the files I should compile first. When I build from the IDE, I get no errors. I tried compiling all of these files separartely using javac command and I got many errors.
myJavaFileView.java
myJavaFileApp.java
myJavaFile.java

Suppose you want to use these three classes.
There are two possibilities:
1. Three separate files called myJavaFile.java,myJavaFileView.java and myJavaFileApp.java. With older Java compilers, it may be necessary to compile the file myJavaFile.java first, with
javac myJavaFile.java
so that the class file myJavaFile.class is found when compiling later the file myJavaFileView.java and myJavaFileApp.java. On newer compilers, this should happen automatically when compiling myJavaFileApp.java and myJavaFileView.java.
2. Put both classes into one file. Note that then only one of these classes may have the public modifier in front of it, as in
public class myJavaFile
which then has to agree with the filename (that is, the file must be called myJavaFile.java).

Bash shell does not recognise 'java', 'javac' commands (Linux command line)

i' ve used javac and java compile & execute commands to build the same application on the DOS command line with Windows - no problem.
But when I try to compile the same file on the command line under Linux Redhat (7.1) using Bash shell i get <bash: javac: command not found> and <bash: java: command not found>.
In both cases I'm using j2sdk1.4.2 downloaded from java.sun.com for Windows & Linux respectively.
I make sure I have both the javac and the file I want to compile in the same directory ../j2sdk1.4.2/bin for both the Windows and the Linux applications.
Is there something I need to do to get bash to recognise javac, java etc? Is there a different setup procedure?
Any angles on this are much appreciated ..

Have you tried these correctly..
Set the CLASSPATH environment variable to include whichever directories you like, eg (on bash) type:
export CLASSPATH=$CLASSPATH:.:<your java dirs>
To make java easier to run, put the directory in which it is installed into your path:
export JAVA_HOME=<where you installed java>
Then do
export PATH=$PATH:$JAVA_HOME/bin
verify it has worked by simply typing
java
You can put all of these commands into the .*rc file for your shell, so that they are executed every time you open the shell. So if you are using bash you can put them into ~/.bashrc
Read up setting the PATH and CLASSPATH for more info.
This shall resolve the issue .

Javac command in Command Prompt

When I compile a .java file in Command Prompt I have to write the whole path to javac.exe - "C:\"Program Files"\Java\jdk1.5.0_07\bin\javac.exe PROBLEM.java"
What do I have to do to so I could write just "javac PROBLEM.java" no mather in which directory I am?
I also have to say that I can run java.exe from any directory but I can't do so with javac.exe
Message was edited by:
vedex

I believe the location of "javac" inside jdk must be
specified in systems variable so that he/she can
compile it and run. His problem is that he wants to type javac MyClass.java rather than C:\jdk\bin\javac.exe MyClass.java In order to do this, he has to alter his PATH variable.
This has nothing to do with Java. This is true of any executable you want to run without specifying the full path.

Javac command line problem

Why might the javac.exe, java.exe, and javaw.exe command lines not stay open? When I open these files, the command line flashes open and immediately disappears.
I tried opening these files using "Run as..." and unchecking the "Protect my computer from unauthorized program activity" option (as my first guess was and still is that I am running into some kind of Windows security settings problem), but this seemed to have no effect.
I am using Windows XP Professional with all updates as of 06-21-2007.

You always want to run executables like that and things like .bat files from a command window. To open a command window, follow jverd's post, reply #2.

Javac - command not found (Linux question)

Hi Im running openSUSE 10.2 and recently downloaded the jdk from sum.com
I added the path of the executable files (home/jdk/bin) to my PATH environment variable, and the command 'java' works fine nomatter what the current directory, 'javac' however claims not to be found, as does appletviewer and many others.
really cant figure this out, seeing as im sure the PATH variable has been set correctly
sorry this is more of a linux question than java but i hoped someone on here might have had the same problem
thanks

use this command to check if javac is in path
which javac if you have set the path correctly, then it should display the location of the javac otherwise it will display an error that no javac found in path..

Javac : command not found ?? A simple question.

Hello.
I need to somehow tell linux where to find javac so that I don't need
to type in /usr/local/jdk1.4/javac HelloWorldApp.java every time I need
to run javac. I have seen how to do this in windows but I don't know how to do it in Linux
I know it's a simple question, I'm just new to Linux.
Your help is appreciated.

The answer depends on the shell you use.
The default on linux is bash, so do this: In your home directory there is a file with the name .bashrc. Commands in that file are performed every time you start the shell.
In that file, add the command "export PATH=/usr/local/jdk1.4/bin:$PATH". Then "source .bashrc" so that the change takes effect. You can verify that the directory has been added with "echo $PATH".
If you want to set the path for all users and not just yourself, make the change in the system startup files. This depends on your distro; the right file might be /etc/profile or /etc/profile.local or /etc/bashrc.

Unable to run JAVAC command at DOS prompt

I installed JDK1.3.1 I gave the pathas
C:\JDK1.3.1 and changed the Autoexec.bat file to have
Set Path=C:\JDK1.3.1\Bin;
When I am trying to run command javac it gives me this message
This program cannot be run in DOS mode
I cant start, Please help
Thanks
Ehsan

Did you reboot the system after the install -- what you put in the autoexec.bat doesn't become effective until the system has been rebooted.
If you don't want to reboot, you can try this:
C:\JDK1.3.1\Bin\javac -classpath C:\JDK1.3.1 HelloWorld.java
V.V.

Javac command

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