repackage failed: Unable to find main class when creating a library using Spring-Boot-Starter-Parent version 2.1.2.RELEASE

Question

I created an example resource server in spring security with a library that contains the WebSecurityConfigurerAdapter. When I update the parent spring-boot-starter-parent in the pom for the library from 2.0.8 to 2.1.2 as well as the spring-boot-maven-plugin I get the dreaded repackage failed: Unable to find main class Version 2.0.8 of the spring-boot-starter-parent doesn't have this issue.

Update: This happens upon doing a mvn clean compile install. A version of the code with parent 2.0.8 can be found here. Just change the pom.xml spring starter parent from 2.0.8 to 2.1.2.

My Library pom is as follows.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example.utils.security</groupId>
  <artifactId>resource-config</artifactId>
  <version>1.0.1</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.2.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
      <version>2.1.2.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>2.1.2.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-config</artifactId>
      <version>5.1.3.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-oauth2-jose</artifactId>
      <version>5.1.3.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework.security/spring-security-oauth2-resource-server -->
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-oauth2-resource-server</artifactId>
      <version>5.1.3.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-web</artifactId>
      <version>5.1.3.RELEASE</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <version>2.1.2.RELEASE</version>
        <executions>
          <execution>
            <goals>
              <goal>repackage</goal>
            </goals>
            <configuration>
              <skip>true</skip>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

</project>

A class to define an annotation.

import com.example.utils.security.resource.autoconfig.ResourceServerConfig;
import org.springframework.context.annotation.Import;

import java.lang.annotation.*;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({ResourceServerConfig.class})
public @interface EnableExampleResourceServer {
}

The WebSecurityConfigurerAdapter

package com.example.utils.security.resource.autoconfig;

import org.springframework.context.annotation.Configuration;
import org.springframework.core.PriorityOrdered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpMethod;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

@Configuration
@EnableWebSecurity
@Order(PriorityOrdered.HIGHEST_PRECEDENCE + 500)
public class ResourceServerConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .csrf().disable()
                .anonymous().disable()
                .logout().disable()
                .formLogin().disable()
                .httpBasic().disable()
                .authorizeRequests()
                .antMatchers(HttpMethod.OPTIONS).permitAll()
                .anyRequest().authenticated()
                .and()
                .oauth2ResourceServer().jwt();
    }
}

Answer 1

The release notes describe that the repackage goal has an identifier now to allow for easier overriding of the repackage execution.

The build above is a bit odd. If you don't want the repackage to occur, why are you defining the goal at all? Just don't define the goal and repackage will not occur as the parent only offers a default execution when the plugin is explicitly defined.

If you need to define it for a different reason, then the link above explains what you should do. Currently, you are redefining a second execution of the repackage goal.