You can create a custom Java Swing client application that lets a user select a file from the local desktop and post the file to an AEM ClientLibs folder. In most AEM applications, you create a ClientLibs folder to store required application files such as CSS file and JS files. In some cases, you can place third-party files like JQuery JS files when you want to incorporate functionality offered by these files into your AEM application.
To develop a Java Swing application that posts files to an AEM client libs folder, you use Java APIs located in the org.apache.http package. The APIs located in this package lets you post files to a custom AEM Sling Servlet. The Sling Servlet saves the file in the specified ClientLibs folder using the JCR API.