Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window elide-graalvm-react-jvm-1.0-v3-alpha4-b12.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.
