To open a JAR file, you need to download and install a compression/decompression utility, such as 7-Zip, that works with JAR files. Once the installation is complete, use 7-Zip to open the JAR file, and extract the individual files contained within it.
- Download and install 7-Zip
Use your Web browser to navigate to the 7-Zip home page, and click on the Download link that points to the executable version of the file. Make sure to select the version that corresponds to the operating system installed on your computer, which is X86 for 32-bit and X64 for 64-bit systems. Once the download is complete, double-click on the executable file, and follow the instructions to complete the installation.
- Extract the contents of the JAR file
Start 7-Zip, and use its navigation section to locate the JAR file you wish to open. Double-click on the JAR file, and use your mouse to mark all the files within it. Click on the Extract button, select the location where you want to extract the files by clicking on the button marked with three periods (…), and click OK.
- Open the individual files
Most of the extracted files should be in the TXT format, meaning that you can use a text processor, such as Notepad, to open the files and peruse the content. If the files inside the JAR package are executable, you need to download Java Runtime Environment from the Java home page and install it. After the installation is complete, double-click on the JAR file to open it directly.