This Maven and Eclipse tutorial shows how to create simple and archetype Maven projects in the Eclipse IDE that can build, compile and install Java code.

To use Java 21, or build applications on an older version of the Eclipse IDE, you must install your preferred version of Java separately and register it as a Java runtime in Eclipse’s preferences ...

Unfortunately there is no standard Java API to send a signal or even get the process ID of a System.Process. An enhancement request has been pending for years (since Java 1.2) to add this.