230412 Docker error

Dockfile

FROM openjdk:17-jdk-alpine
ARG JAR_FILE=build/libs/*.jar -> download jar's path
COPY ${JAR_FILE} demo-0.0.1-SNAPSHOT.jar
ENTRYPOINT ["java","-jar","/demo-0.0.1-SNAPSHOT.jar"]

Error

A problem occurred evaluating root project 'myProject'.

Could not set unknown property 'mainClassName' for extension 'springBoot' of type org.springframework.boot.gradle.dsl.SpringBootExtension.

Answer :
in the bulid.gradle

springBoot {
mainClass = 'com.mir3.service.contactfileparser.Main'
}