How run a java program without bluej

[Arik Shalito]

Hey
Im new to java programming and i have a silly question.

I made a program, compiled and ran it in bluej.
My question is, How can i send it to my friend (knows nothing about java..) so he can run it by simply double clicking.

Edit:
Someone from another forum said i have to make a gui to my program, Is that true? Because i dont really know how to do it and im gonna waste alotta time sittin on it...

Thanks in acvance

[Campbell Ritchie]

Welcome to the Ranch

I have suffered from BlueJ myself and do not like it.
You need a main method which you can read about here. It should be short, very short. If you have a simple app with all classes in the unnamed package and you are using class Foo to contain the main() method, you open a command prompt/terminal and navigate to your directory and write
javac Foo.java
java Foo
More details in this FAQ.

[Campbell Ritchie]

Arik Shalito wrote:. . . i have to make a gui to my program, Is that true? . . .

No.

The easiest way to send it across the Net is to create a .jar file. You need to add the name of the class with the main() method in the manifest file. That all sounds very complicated but there are instructions in the Java™ Tutorials. Look particularly at the section about setting the entry point.

[Tony Docherty]

No you don't need to write a gui to be able to run a Java program by double clicking on it. In fact having a GUI or not having one makes no difference to how you run your program.

What you do need to do is package your class file(s) in a jar (with a suitable manifest file) and then your friend needs to have Java installed on his machine. Then when he double clicks the jar it will launch your program. BlueJ will probably have an option for building a runnable jar but I've never used BlueJ so can't advise on how you use it, alternatively you can do it manually from the command line.

[Arik Shalito]

import java.util.Scanner;

public class Shelf
{
    public static void main(String[] agrs)
    {
        final double W = 0.5; // boundregel
        
        double x; //board length
        double y; //shelf thickness
        double z; // shelves num
        double fh; // first hole
        double d; // distanse between the shelves
        
        Scanner input = new Scanner(System.in);
        System.out.println("Enter boards length in cm: ");
        x = input.nextDouble( );
        System.out.println();
        
        System.out.println("Enter shelves thickness in cm: ");
        y = input.nextDouble( );
        System.out.println();
        
        System.out.println("Enter the number of shelves: ");
        z = input.nextDouble( );
        System.out.println();
        
        d = (x/(z+1));
        fh = d-(y/2)-W;
        
        System.out.println("The first hole is " + fh + " cm from the bottom.");
        int i;
        double nh = fh + d;
        double k = fh;
        for(i=0; i<z-1; i++)
        {
            k = k + d;
            System.out.println("The next hole is " + k +  " cm from the bottom.");
        }        
    }
    
}

Before i do anything, I wanna make sure theres nothing missing for that.

Again, excuses for the newbism...
and thanks for the welcoming

[Les Morgan]

I have never used BluJ, but use NetBeans all the time--at this point many of the IDE's have executable JAR options. Your program looks fine at a glance, as you have never said it does not run I will assume that it does. You need to make an executable JAR file. This is probably an option in BluJ, but be advised if you make an executable JAR and he has the JRE installed locally, he will run the file alright, but when the program is done, it will exit and close the console window immediately, so he will not be able to sit and look at the result of your program.

You can run the class file by itself "javaw Shelf" or possibly "javaw Shelf.class" this has to be done at a console window and javaw.exe has to be in the path statement of the local machine. Also you will need to be in the folder where your Shelf.class file is located.

You can do the same thing using an executable JAR, so the window will stay open you open a console window and type "javaw -jar Shelf.jar" provided your executable JAR file is called Shelf.jar or just double click on the JAR file from file browser and it's going, but like I said it will close the window as soon as your program is done.

[Campbell Ritchie]

javaw Shelf
Not:-
javaw Shelf.class

[Knute Snortum]

To create an executable jar file in BlueJ, open a project, File -> Create Jar File..., and select the main() method that launches the program. (At least, I believe this is how you do it.)

[Arik Shalito]

thanks tony and campbell, I followed the tutorials
but still:

I have set the JAVA_HOME and PATH enviroment variables:
added "%JAVA_HOME%\bin;" to the system variable PATH


command prompt:
this seem to work

C:\Program Files\Java\jdk1.8.0_60\bin> javac -version
javac 1.8.0_60

this didnt, and i have no idea why... X_x

C:\Users\Shalitovsky\Desktop\Java projects\Shelf> javac Shelf.java
'javac' is not recognized as an internal or external command,
operable program or batch file.

Les Morgan, the fact that I wont be able to see the end results is something I didnt take in consideration, i will add a piece of code to it, Thanks
but thats something i could find out if id be able to run it :<

Knute Snortum, I created an executable jar through bluej,
it has Java's icon, but when I double click it, nothing happens

[Tony Docherty]

Open up a command prompt and type:
set <ENTER>

Now check the output to see if the JAVA_HOME variable is pointing to "C:\Program Files\Java\jdk1.8.0_60" and PATH includes "C:\Program Files\Java\jdk1.8.0_60\bin"

[Campbell Ritchie]

That is because you have set your PATH wrongly. If you nagivate to the folder with javac.exe in, the OS will be able to find it easily. If you are in a different folder and your PATH is set wrongly, how can it find javac?
Please read this how‑to and post the result of your writing
echo %PATH%
at the command line.

[Arik Shalito]

Tony, 'the syntax of the command is incorect'

Ritchie,
echo %PATH%

%JAVA_HOME%\bin;
C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMD APP\bin\x86;
C:\ProgramData\Oracle\Java\javapath;
C:\Program Files (x86)\Intel\iCLS Client\;
C:\Program Files\Intel\iCLS Client\;
C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;
C:\Windows\System32\WindowsPowerShell\v1.0\;
C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT 

echo %CLASSPATH%

%CLASSPATH% 

[Knute Snortum]

It looks like you don't have the environment variable JAVA_HOME set. Do you know how to set it?

[Arik Shalito]

No sir, But i googled it and I wish its the last obstacle:

For Korn and bash shells, run the following commands:

export JAVA_HOME=jdk-install-dir

export PATH=$JAVA_HOME/bin:$PATH

For the bourne shell, run the following commands:

JAVA_HOME=jdk-install-dir

export JAVA_HOME

PATH=$JAVA_HOME/bin:$PATH

export PATH

For the C shell, run the following commands:

setenv JAVA_HOME jdk-install-dir

setenv PATH $JAVA_HOME/bin:$PATH

export PATH=$JAVA_HOME/bin:$PATH

I have no idea which shell I need.

[Knute Snortum]

You're in windows so the shell is CMD.EXE. If you search for Command Prompt in the start menu, you should find it, or just type CMD.EXE in the space under the start menu (or in windows 10, in the search).

So you're at a command prompt. To set JAVA_HOME for just this session, type

> set JAVA_HOME="C:\Program Files\Java\jdk1.8.0_60"

You should be able to type

> javac -version

and get a version number. Now to set it permanently, type

> setx JAVA_HOME %JAVA_HOME%

[Campbell Ritchie]

Knute Snortum wrote:. . . If you search for Command Prompt in the start menu . . .

Start Menu→All Programs→Accessories→Command Prompt

Sorry got it wrong first time and had to add Accessories.

[Arik Shalito]

cmd:

C:\Users\Shalito>setx JAVA_HOME %JAVA_HOME%

SUCCESS: Specified value was saved.

C:\Users\Shalito>javac -version
'javac' is not recognized as an internal or external command,
operable program or batch file.

[Tony Docherty]

setx JAVA_HOME %JAVA_HOME% will only work if you've previously done set JAVA_HOME="C:\Program Files\Java\jdk1.8.0_60" in the same command window.

[Arik Shalito]

Well yes, I did do what Knute Snortum told me:

So you're at a command prompt. To set JAVA_HOME for just this session, type

?
1
> set JAVA_HOME="C:\Program Files\Java\jdk1.8.0_60"


You should be able to type

?
1
> javac -version


and get a version number. Now to set it permanently, type

?
1
> setx JAVA_HOME %JAVA_HOME%

and still javac -version isnt working

[Campbell Ritchie]

Where does the 1 come from?
Did you set the JAVA_HOME variable before using setx?

[Knute Snortum]

Try this. From a command prompt, type

cd %JAVA_HOME%\bin
then
javac -version
Do you get a Java version number? If not, then type
echo %JAVA_HOME%
and post it.

If you do see a version number, type
path
Do you see C:\Program Files\Java\jdk1.8.0_60\bin; in there? If not, post the PATH.

[Arik Shalito]

Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.

C:\Users\Shalito>cd %JAVA_HOME%\bin
The system cannot find the path specified.

C:\Users\Shalito>javac -version
'javac' is not recognized as an internal or external command,
operable program or batch file.

C:\Users\Shalito>echo %JAVA_HOME%
C:\Users\Shalito\.nbi\product-cache\jdk\1.8.0.60.2764

[Campbell Ritchie]

What a peculiar JAVA_HOME. Try

set PATH="C:\Program Files\Java\jdk1.8.0_60\bin";%PATH%

at the command prompt. That assumes you installed JDK8u60 in its default location and that you have C as your default drive letter. Then try
javac -v
again.

[Arik Shalito]

C:\Users\Shalito>set PATH="C:\Program Files\Java\jdk1.8.0_60\bin";%PATH%

C:\Users\Shalito>javac -v
javac: invalid flag: -v
Usage: javac <options> <source files>
use -help for a list of possible options

[Campbell Ritchie]

That suggests you have a correctly‑set PATH now. It should have been
javac -version
Sorry for that mistake.

[Arik Shalito]

I am sorry for the headache,

C:\Users\Shalito>javac -version
'javac' is not recognized as an internal or external command,
operable program or batch file.

[Campbell Ritchie]

How on earth did you manage that? Have you closed the command prompt? The set PATH instruction is only applied to the current command window.

[Arik Shalito]

Yes, I closed it after the first time I wrote it with "javac -v", Thanks for the information.

Did it again the right way:

C:\Users\Shalito>set PATH="C:\Program Files\Java\jdk1.8.0_60\bin";%PATH%

C:\Users\Shalito>javac -version
javac 1.8.0_60

[Campbell Ritchie]

That looks more like it Now try running your program.

Look in the Java™ Tutorials and the Oracle installation instructions. About halfway down it tells you how to set the PATH. But put your new PATH entry at the beginning of the system PATH. Unfortunately you will have to update it when the next version of Java® becomes available.

[Arik Shalito]

my "Shelf.jar"
does nothing when I double click it, But let me read those first I got alot of info to read...
I'll post if nothing goes

Thank you very much so far!

[Knute Snortum]

Hmm... mine didn't work either. Maybe there's something I don't know about creating an executing jar in BlueJ. It did work when I did

java -jar MyClass.jar

[Arik Shalito]

Well hey thats the first time I see my program not through IDE *_*
I wrote this:

Knute Snortum wrote:
java -jar MyClass.jar

But yea I really want to make it work by simply double clicking the jar file, Dont get me wrong.. I dont care if its through bluej netbeans .. or w/e...

[Knute Snortum]

I think I have it. It goes back to that "GUI" comment someone made. If you type this at a command line:
ftype jarfile
you will probably get something like this:
jarfile="C:\Program Files\Java\jre1.8.0_60\bin\javaw.exe" -jar "%1" %*

That says basically that you should execute javaw to launch a jar file. But javaw doesn't create a command window! So you can't see a project that only sends output to System.out.println. It works best with GUI projects where you don't want a command window opened.

The solution on your PC is to just execute
java -jar MyMainClassJar.jar
but this isn't going to work well if you want to send it to someone else. You could create a batch file like this
@java -jar MyMainClassJar.jar
and save it as MyMainClass.bat.

[Arik Shalito]

Thank you thats what I need!!

Thanks everyone! I love this forum :]

[Campbell Ritchie]

You're welcome