To send a WhatsApp message in 30 seconds using Java and Gradle, you need to set up a Twilio account and enable the WhatsApp Business API. You'll need Java 11, Gradle 7.1, a Twilio account, IntelliJ Idea Community Edition, and a smartphone with WhatsApp installed. After setting up your project and obtaining an ACCOUNT SID and AUTH TOKEN, you can use these values to initialize the Twilio client and send a message using the `Message.creator()` method. The code initializes the Twilio client, constructs a message, and sends it when the `create()` function is run, printing the Message SID on the terminal. After setting up the project, you can run it and receive a WhatsApp message on your device.