Here you can find how to create .jar in Netbeans: How to create a Jar file in Netbeans
You can run the executable jar on every single computer, on one condition - the system have JRE installed.
If you want to, you can also build the .jar using command line, to do that use the following command:
jar cf jar-file input-file(s)
Description from Oracle doc:
The options and arguments used in this command are:
The c option indicates that you want to create a JAR file. The f
option indicates that you want the output to go to a file rather than
to stdout. jar-file is the name that you want the resulting JAR file
to have. You can use any filename for a JAR file. By convention, JAR
filenames are given a .jar extension, though this is not required. The
input-file(s) argument is a space-separated list of one or more files
that you want to include in your JAR file. The input-file(s) argument
can contain the wildcard * symbol. If any of the "input-files" are
directories, the contents of those directories are added to the JAR
archive recursively. The c and f options can appear in either order,
but there must not be any space between them.
This command will generate a compressed JAR file and place it in the
current directory. The command will also generate a default manifest
file for the JAR archive.