1. Error record

function

class Student1 {
}

Groovy code will report an error;

Error message:

groovy.lang.GroovyRuntimeException: This script or class could not be run.
It should either:
- have a main method,
- be a JUnit test or extend GroovyTestCase,
- implement the Runnable interface,
- or be compatible with a registered script runner. Known runners:
  * <none>

2. Problem analysis

Only groovy code that meets the following requirements can run:

With main function

test case, used as JUnit test or extended GroovyTestCase

Thread related and implements the runnable interface
It is compatible with the registered script running program

Groovy code in other cases cannot be run;