To run a JAR file, install Java, open a command prompt or Terminal, and run java -jar "/path/to/file.jar" with the file’s actual path. This works only if the JAR is packaged as a launchable application with a Main-Class entry in its manifest. If you only want to see what files are inside, inspect or extract the archive instead of trying to run it.
First decide: run the JAR or inspect its contents?
A JAR is a Java archive. It can contain program files and other resources, but not every JAR is an application that can start on its own. To launch one with Java’s -jar option, its manifest must name a startup class with a Main-Class header. Oracle documents this requirement in its Java SE 21 launcher documentation.
- Run it if you intend to use the program and its publisher provides instructions for launching it.
- Inspect or extract it if you only need to view the archive’s contents. Extracting a JAR does not make a non-launchable JAR into an application.
Only run a JAR from a source you trust. Verify the publisher and the file before launching downloaded code; do not bypass an operating-system warning just to make it open.
Run a JAR from the command line
- Install Java. Install a Java runtime or JDK appropriate for the application and your operating system. Microsoft documents installation routes for Windows, macOS, and Linux, including Windows EXE or ZIP installers, macOS PKG or TAR.GZ packages, and Linux DEB or RPM packages. See Microsoft’s OpenJDK installation guide. The application’s own instructions should specify any Java version requirement.
- Open a command-line window. On Windows, use Command Prompt or PowerShell. On macOS or Linux, open Terminal.
- Check that Java is available. Enter
java -version. If the command is not found or recognized, Java may not be installed or its launcher may not be on your PATH. - Run the JAR. Enter
java -jarfollowed by the JAR’s path. For example:java -jar "/path/to/My App.jar". Replace the example path with the file’s actual location. Keep quotation marks around paths that contain spaces.
The documented command form is java [options] -jar jarfile [args ...]. Any arguments after the JAR filename are passed to the application’s main() method. See Oracle’s Java command reference.
#1 Best Overall
- USB-C 2-in-1 storage OTG: The Lexar JumpDrive Dual Drive D40E features USB Type-A and Type-C connectors in a slim, portable form factor for easy device compatibility
- Transfer speeds up to 100MB/s: Based on internal testing, performance may vary depending upon the host device, interface, and usage conditions. 1MB=1,000,000 bytes
- Plug and Play: Widely compatible with USB Type-C smartphones, tablets, laptops, Macs, and traditional Type-A devices, no software installation required. The 360° swivel design allows for easy switching between connectors without the hassle of losing a cap
- Durable & Compact: The Lexar D40E USB memory stick features a metal enclosure, withstands temperatures from 0° to 50° C (32°F to 122°F), and is lightweight at 26g with dimensions of 70.4 x 16.9 x 11.7mm
- Security & Warranty: Securely protects files using an advanced security software solution with 256-bit AES encryption. Backed by a Lexar 3-year limited warranty
Platform-specific notes
Windows
The command-line steps above work on Windows when Java is installed and available. Microsoft’s Windows installer includes a FeatureJarFileRunWith option to associate JAR files with Java applications, but double-click behavior depends on that association being configured. If double-clicking does nothing or opens an archive viewer, try the command line to check whether Java can launch the file.
Oracle also documents javaw, a Windows launcher that behaves like java but does not open an associated console window. It can still display a dialog if launch fails. For initial troubleshooting, java -jar is usually more informative because errors appear in the command window.
Rank #2
- High-speed USB 3.0 performance of up to 150MB/s(1) [(1) Write to drive up to 15x faster than standard USB 2.0 drives (4MB/s); varies by drive capacity. Up to 150MB/s read speed. USB 3.0 port required. Based on internal testing; performance may be lower depending on host device, usage conditions, and other factors; 1MB=1,000,000 bytes]
- Transfer a full-length movie in less than 30 seconds(2) [(2) Based on 1.2GB MPEG-4 video transfer with USB 3.0 host device. Results may vary based on host device, file attributes and other factors]
- Transfer to drive up to 15 times faster than standard USB 2.0 drives(1)
- Sleek, durable metal casing
- Easy-to-use password protection for your private files(3) [(3)Password protection uses 128-bit AES encryption and is supported by Windows 7, Windows 8, Windows 10, and Mac OS X v10.9 plus; Software download required for Mac, visit the SanDisk SecureAccess support page]
macOS
Use Terminal and the same java -jar command. Microsoft documents macOS installation options including PKG, TAR.GZ, and Homebrew. Double-clicking is not guaranteed to work: it depends on the local file association and the JAR’s contents.
Linux
Use Terminal and the same launcher command. Microsoft documents Linux installation routes that include DEB and RPM packages, as well as distribution-specific instructions. Desktop file associations vary by Linux environment, so the command line is the clearest general method.
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Rank #3
- What You Get - 2 pack 64GB genuine USB 2.0 flash drives, 12-month warranty and lifetime friendly customer service
- Great for All Ages and Purposes – the thumb drives are suitable for storing digital data for school, business or daily usage. Apply to data storage of music, photos, movies and other files
- Easy to Use - Plug and play USB memory stick, no need to install any software. Support Windows 7 / 8 / 10 / Vista / XP / Unix / 2000 / ME / NT Linux and Mac OS, compatible with USB 2.0 and 1.1 ports
- Convenient Design - 360°metal swivel cap with matt surface and ring designed zip drive can protect USB connector, avoid to leave your fingerprint and easily attach to your key chain to avoid from losing and for easy carrying
- Brand Yourself - Brand the flash drive with your company's name and provide company's overview, policies, etc. to the newly joined employees or your customers
Phones and tablets
The installation guidance cited here covers desktop operating systems; it does not establish a universal on-device JAR launcher for phones or tablets. Check whether the application supports your specific device and operating system rather than assuming a JAR will run natively.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why won’t my JAR file open?
The system says Java cannot be found
Check whether Java is installed and whether its launcher is on PATH, then retry java -version. Microsoft says its native Windows and macOS installers make JDK tools available in PATH; archive-based installations require environment setup. Follow the instructions for the installation method you chose.
Rank #4
- GOOD VALUE PACKAGE - 1 Pack 32GB Memory Stick USB 2.0 Flash Drives with great cost performance and high quality.
- BIG CAPACITY - The available capacity: 29.10GB-29.8GB, You can save the data of movies, music, photos, designs, programs, manuals, handouts in a high speed.Good performance in digital data storing, transferring and sharing with families, friends, workmates, clients and machines.
- EASY TO USE & PLUG AND WORK - Support windows 7 / 8 / 10 / Vista / XP / 2000 / ME / NT Linux and Mac OS, Compatible with USB2.0 and below.
- TWISTTURN DESIGN & EASY CARRY - The metal clip rotates 360° round the ABS plastic body which with rubber oil skin feeling finish. The capless design can avoid lossing of cap, and providing efficient protection to the USB port.
- WARRANTY & SUPPORT - SIMMAX logo is laser printed on the USB connector surface, our products are of good quality and we promise that any problem about the product within one year since you buy.
Double-clicking does nothing or opens an archive viewer
Double-clicking depends on a file association; it does not prove that the JAR is a runnable application. Try launching it from a command line. If Java reports that the archive has no main manifest attribute or cannot find a main class, the JAR may not have the startup entry point required by java -jar.
The JAR has no main manifest attribute or main class
A JAR without a Main-Class entry is not launchable with the documented -jar form. It may be a library or an archive intended for another program. Ask the distributor for the correct command or application launcher; installing an extractor or changing the file association will not supply the missing entry point.
Best Value
- 【16GB Flash Drive】USB flash drives with 16GB capacity, meet your needs of daily use on work, school, home and travelling for photos, music, videos, files storage and transfer. IMEASON thumb drives can be used to store different files, easy to data backup.
- 【Metal Swivel Cap Design】USB thumb drive is metal swivel cover provides extra protection for the usb thumbdrive connector, no usb drive cap to lose; keychain design makes it easier to carry without worrying lose it.
- 【Wide Compatibility】USB drive supports Windows 7/8/10/11 / Vista / XP / Unix / 2000 / ME / NT Linux and Mac OS, also Supports USB 2.0 and 1.1 ports. USB Stick support TV, desktop, notebook computer, car, audio and other device. The USB Memory Stick is your great data storage and transfer companion with traveling and working.
- 【Easy to use】usb memory stick is plug and play without any software installation. Just simply plug the Flashdrive into the port of your USB-compatible devices such as computer, laptop to start data storage or transmission.
- 【What You Get】16 GB USB Flash Drive Thumb Drive, The default format of the usb storage flash drive is FAT32.
Java reports a version or compatibility error
The required Java version depends on the application, and there is no single version requirement for all JAR files. Check the application publisher’s official instructions rather than guessing or repeatedly installing different Java versions.
A security warning appears
Do not bypass the warning without verifying the file’s source and integrity with its publisher. The right response depends on the warning and operating system; if you cannot verify the download, do not run it.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
