Message pop-ups are not allowed for Spring Boot projects. You can use windows or HTML. Java.awt.HeadlessException: null exception will occur when pop-ups
Steps to solve java.awt.HeadlessException:
1. Delete in the startup class of springboot
SpringApplication.run(Application.class, args)
2. Replace with
SpringApplicationBuilder builder = new SpringApplicationBuilder(Application.class);
builder.headless(false).run(args);
3. In the eclipse installation directory, find the eclipse.ini file, and add at the end: -Djava.awt.headless=false. Just restart
