Right click on the project and choose Export > Java > JAR file.
You can deselect the .classpath and .project files to avoid polluting your jar with unwanted files only used by Eclipse.
Select the export destination. You may choose to export the jar directly into your /ServoyInstallDir/application_server/plugins directory.
Leave the 2 “Export "Export class files…” files…" checked, and check the “Save "Save the description of this JAR in the workspace”workspace". Use the browse button to navigate to your project, and give a name to your definition. Eclipse automatically adds the “jardesc” "jardesc" extension.
What is nice about this option is that the next time you will want to deploy your jar (with modified sources for example), all you will have to do is right-click on the file “xxx"xxx.jardesc” jardesc" in the Package explorer and choose “Create JAR” "Create JAR" in the menu, with no need to go through all the Export dialogs each time you change something in your plugin.
Click Next once more. You may leave it as is, or choose other options.