README.md show how to generate standalone jar file.

README.md

@@ -53,3 +53,11 @@ popd
 
 ```
 
+
+# Generate jar file
+
+```shell
+$ mvn package
+$ cd unl-tools-main/target
+# you should see unl-tools-main-0.9.jar that is the standalone jar file.
+```
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