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 is executed with terminal but not with direct clicking

I have tried the following:
in terminal it works
In Intellij it works
I have tried to launch it with javaw.exe but nothing changes
Are there any other options?

This looks like an OS problem that an application building one -- because you said that it works in your IDE and terminal.
Make sure that you installed Java properly in your machine.
In Windows/MacOs, after installing Java, the *.jar files are automatically associated with the java -jar command and makes it runnable via double-click.
In linux, this varies on the flavour or DE you are using. But there's probably a utility in your OS to open *.jar files using java -jar command.

SSH ramdisk tool not running

First thing I installed Java jdk and jre
Then I installed a file called ssh_rd_rev04b.jar
I tried to open the jar file but it didn't run
I double clicked it,
I made a .bat file and typed java -jar filename didn't work too, tried other things but didn't work as well .
Please help .

Java application export

Okay so I have been coding a game for a while now and I am hoping to release its alpha just one problem. I don't know how to export it and run it. Please note that all my code works fine. So when I export it I export it as a Runnable jar file once I do so I set it and have tried both exporting it as .jar and .exe. Once I exported it I tested it by clicking the resulting file but it doesn't open the application but rather it opens it in eclipse encoded. Please help I may just be an idiot.

you have to try to launch it with:
java -jar yourrunnable.jar
If you plan to run on windows and you want a .exe file, try to check this SO question: How can I convert my Java program to an .exe file?
or if you want to target a mac, you can have a check here:
http://docs.oracle.com/javase/7/docs/technotes/guides/jweb/packagingAppsForMac.html
Basically any platform you target you have some customization in order to achieve a seamless run. Anyway the most cross platform solution is the Java -jar way.

I had the same problem with .jar files not opening on a double click. It turned out that I had two versions of Java installed (Java 6 and 7). Uninstalling Java 6 from Control Panel-> Uninstall a Program was what finally allowed .jar files to open on a double click without using the command window.
What is listed in right-click-> Open With ? Is some other program listed as the default program ? Is a Java Runtime listed ? If a Java Runtime is listed, you can open with it, and make it the default program to run with.
Right Click -> Properties -> Change -> C:\Program Files\Java\jre7\bin\javaw.exe
For Java 8 use below
java.exe -jar myFile.jar

Possible to run JAR file on any OS?

Is it possible to execute a JAR file on any OS (like Windows, Linux, Mac OS X)? I want to build a simple application that I want to run on Linux, Windows, and Mac OS X. Could the JAR file be run on any OS with java installed?

The Jar files run on any OS for which a JVM exists.

Yes, as long as you don't use any native libraries (JNI) this is how java works. It's platform independent.

As other said, as long as you have Java installed and avoid using native code, you should be good to go. One thing to note is that you can usually run a JAR file just by double clicking it, and it opens like a native executable (on Windows this is how it works by default, on other OSes you can configure this behavior).
Such JAR files are called executable JAR files. If what you want to create is an executable JAR file, then you need to add a manifest file that tells the Java virtual machine (JVM) the name of the main class. Executable JAR files also can be run on the command line by doing:
java -jar myprogram.jar
If your JAR is not an executable JAR, then to run your program you have to add the JAR to your classpath and then execute the main class. To add a JAR to the classpath:
java -classpath path/to/your/program.jar com.mypackage.Main

Jar files are designed to run on any OS that has a JVM of a compatible version installed. Some jar files, however, may have be compiled from Java code that used OS-specific code (say talking to Windows registries), so testing it on other OS's is wise.

Yes, it can as long as it's not ruining from the terminal or command prompt (like java -jar name.jar.) it should work just fine.