Develop Reference

Cannot open .jar files with java installed (windows 11)

Environment: Windows 11
Problem: cannot open .jar file(the MARS assembly language simulator)
Hello, I am currently trying to install the MARS assembly language simulator. It is a .jar file so I downloaded java to open it. However, I still can't open the file even with java downloaded.
I checked if java was installed using my cmd:
Command prompt showing java successfully installed
I tried double-clicking it did not work. So I right-clicked it to open with other apps. But I did not see java in the given options.
Cannot find the java option to open the file
Thank you so much for helping!

Use your prompt
CD into the directory with the jar
then execute
java -jar Mars.jar
...any more troubles , open file properties tab with right click on the jar and check permissions to execute the file.

Installing Java usually means installing a JVM, which is a Java Virtual Machine. You won't be able to launch files from a Windows context menu like this, because "Java" is not a program that opens files.
Instead you need to:
Either a terminal and call javaw.exe with the parameters -jar and your .jar-file. E.g.:
C:\your\java\binaries\javaw.exe -jar -SomeJarFile.jar
Or add the Java installation to your environment variables, then you can call javaw.exe without providing some specific path

.jar file is not working after being published from Eclipse [duplicate]

There was a program that I used that made runnable .jar files.. All the ones I'm finding now are ones that make .exe files.. I remember it also has the option to make the file a .sh script as well. Anyone knows its name? I've been searching for hours with no avail :/

The command line
java -jar file.jar
Will run your jar file if it has a Main-Class defined as explained here.
You can use that command in a shell script.

You can create a runnable jar using NetBeans IDE or Eclipse IDE by just providing the main class to run. Rest of the things it will take automatically. That class must be having a main() method in it. Then you can run that jar file using java -jar yourjarfile.jar

Do you mean actually coding java and then compiling to .jar? If you do try
eclipse code editor
I used eclipse to make minecraft mods. It will work if you want to make .jar programs.

If you want to have a jar that you can execute using the usual syntax ./app.jar (instead of java -jar), here is a post explaining the process: how to create executable jars.
Basically, JAR is a variant of ZIP, which allows random bytes to be pre/appended to the JAR without corrrupting it. This means it is possible to prepend a launcher script at the beginning of the jar to make it "executable".
Here is a simple example of the process:
# Append a basic launcher script to the jar
cat \
<(echo '#!/bin/sh')\
<(echo 'exec java -jar $0 "$#"')\
<(echo 'exit 0')\
original.jar > executable.jar
# Make the new jar executable
chmod +x executable.jar
With this, you can now run ./executable.jar instead of java -jar original.jar. This works on all unix like systems including Linux, MacOS, Cygwin, and Windows Linux subsystem.

java 'jar' is not recognized as an internal or external command

I'm getting the following error when I try to run the 'jar' command in the command line on windows :
'jar' is not recognized as an internal or external command
The general solution seems to be that I need to add the jdk bin folder to the PATH in environment variables. I have already done this, I added the following to the path variable :
...; C:\Program Files\Java\jdk1.8.0_40\bin\;
Though I'm not sure if having the jdk reside in 'program files' instead of 'program files x86' affects this. I'm on 64 bit windows with 64 bit java.
Thanks

The path should only contain directories where the OS will look for executables. Strip the trailing "\jar.exe" to set your path as:
(old path variables here);C:\Program Files (x86)\Java\jdk1.7\bin
Thanks To : #stevevls

Try using this command:
java -version
If it doesn't work that means you failed to properly add path to jdk.
If it does work, try using:
java -jar

The jar command in command line is used in order to create a JAR file. For example:
jar cf jar-file input-file(s)
See more at: Oracle docs
If you want to run the existed JAR file you should use the java -jar command mentioned by #Aleksandr.
But in your case it looks like you don't have an access to the added directory in your path with JKD binaries so at the beginning try to execute mentioned java --version to check whether you have java in you classpath at all.
Please remember that on Windows you have to restart the console when you change the windows default path. You do not see the changes on the current console.
The x64 version of Java is installed on Program Files. The x86 version is installed on Program Files x86 by default.

Five steps to solve this problem:
check whether in your bin folder jar.exe is availbale or not
check for your environmental setting
download jar file from here http://originaldll.com/file/jar.exe/29248.html and keep in bin folder
now check for jar it will 100% work
keep any jar in your desktop and go to desktop path on cmd prompt and run the command jar xf filename.jar
Now see if it is working

how to run jar file on RHEL5?

I have made a jar file which i tested in windows and it works fine. now i want to test it for red hat enterprise linux 5. but i dont know how to run jar files in rhel5.
i've tried java -jar My.jar but it says bash: java: command not found. i've set JAVA_HOME variable as export JAVA_HOME=/root/jdk1.6.0_21 but still not working.
can anybody tell me how to run jar file in rhel5?

You need to set PATH variable , something like
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin
replace /usr/java/jdk1.5.0_07/bin with path to your jdk's bin directory.
The problem is your terminal tries to find java command from the PATH , but it couldn't find it.
Update:
You need to setup global config in /etc/profile OR /etc/bash.bashrc file for all users:
# vi /etc/profile
Next setup PATH / JAVA_PATH variables as follows:
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin
export PATH=$PATH:/usr/java/jdk1.5.0_07/bin

Top tip but slightly off topic.
1) Install your JDK in /usr/local/jdkX.X.X_XX/
2) Create a symbolic link /usr/local/java -> your chosen JDK installation
When you install new versions of java or if you want to revert to an older version, just change the symbolic link.

Running a Java 3D program from the command line

I recently installed java 3D in my computer and it all the progras which I created worked from the NetBeans IDE. However when i set the path in the command line, it says that javac is not ercognised.
I set the path to,
C:\Program Files\Java\Java3D\1.5.1\bin
and then typed javac FirstProgram.java
I got the following mesage (please help)
'javac' is not recognized as an internal or external command,
operable program or batch file.

If you have compiled your project in NetBeans already, then to run it you use java not javac.
If you can export your built project as a JAR (would be in dist folder of your project), you can run it with java -jar myProgram.jar
javac is the Java compiler, should be where you have put the JDK, not Java 3D.

Setting the path to Java3D won't help you much. It's important that the Java3D jars (you can find them if you look around the stuff in that directory) are on your classpath when you execute your program. So to augment Bakkal's suggestion, you need something like
java -cp "C:\Program files\Java\Java3d\lib\xxx.jar" -jar myProgram.jar
The path to your 3D jar is in quotes because of the usual trouble with blanks in a directory name. This is one of Microsoft's most stupid mistakes!