Can't compile

When I execute `./mvnw clean package`, I get an error. The error message is as follows:

```
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 166, column 21
[ERROR] 'dependencies.dependency.version' for junit:junit:jar is missing. @ line 175, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 97, column 21
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-test:jar is missing. @ line 102, column 21
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 133, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 87, column 21
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-test:jar is missing. @ line 92, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 200, column 17
[WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-context:jar -> duplicate declaration of version (?) @ line 237, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 199, column 21
[WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-context:jar -> duplicate declaration of version (?) @ line 258, column 21
[WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-context:jar -> duplicate declaration of version (?) @ line 155, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 131, column 21
[ERROR] 'dependencies.dependency.version' for junit:junit:jar is missing. @ line 196, column 21
[FATAL] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 97, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 156, column 21
[WARNING] 'build.plugins.plugin.version' for org.springframework.boot:spring-boot-maven-plugin is missing. @ line 87, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 198, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 185, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 193, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 200, column 21
[WARNING] 'build.plugins.plugin.version' for org.springframework.boot:spring-boot-maven-plugin is missing. @ line 218, column 21
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead. @
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 200, column 21
[WARNING] 'build.plugins.plugin.version' for org.springframework.boot:spring-boot-maven-plugin is missing. @ line 217, column 21
[WARNING] The expression ${artifactId} is deprecated. Please use ${project.artifactId} instead. @
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ org.apache.dubbo:dubbo-samples-protobuf:1.0-SNAPSHOT, dubbo-samples/dubbo-samples-protobuf/pom.xml, line 140, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ org.apache.dubbo:dubbo-samples-protobuf:1.0-SNAPSHOT, dubbo-samples/dubbo-samples-protobuf/pom.xml, line 140, column 21
[WARNING] 'build.plugins.plugin.version' for org.codehaus.mojo:build-helper-maven-plugin is missing. @ line 140, column 21
[WARNING] 'build.plugins.plugin.version' for org.springframework.boot:spring-boot-maven-plugin is missing. @ line 92, column 21
[WARNING] 'build.plugins.plugin.version' for org.springframework.boot:spring-boot-maven-plugin is missing. @ line 90, column 21
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 19, column 17
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 49, column 21
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-jar-plugin is missing. @ line 61, column 21
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 56, column 25
@
[ERROR] The build could not read 7 projects -> [Help 1]
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-async-onerror:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-async/dubbo-samples-async-onerror/pom.xml) has 3 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 166, column 21
[ERROR] 'dependencies.dependency.version' for junit:junit:jar is missing. @ line 175, column 21
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-configcenter-externalconfiguration:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-configcenter/dubbo-samples-configcenter-externalconfiguration/pom.xml) has 3 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 97, column 21
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-test:jar is missing. @ line 102, column 21
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-docker:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-docker/pom.xml) has 3 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 87, column 21
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-test:jar is missing. @ line 92, column 21
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-jetty:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-jetty/pom.xml) has 2 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 200, column 17
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-resilience4j-filter:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-resilience4j/dubbo-samples-resilience4j-filter/pom.xml) has 2 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 199, column 21
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-rest:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-rest/pom.xml) has 3 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-simple:jar is missing. @ line 131, column 21
[ERROR] 'dependencies.dependency.version' for junit:junit:jar is missing. @ line 196, column 21
[ERROR]
[ERROR] The project org.apache.dubbo:dubbo-samples-spring-boot-hystrix:1.0-SNAPSHOT (dubbo-samples/dubbo-samples-spring-boot-hystrix/pom.xml) has 2 errors
[ERROR] The parents form a cycle: org.apache.logging.log4j:log4j-bom:2.7 -> org.apache:apache:9 -> org.apache:apache:9 @ org.apache.maven:maven-parent:19
[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter:jar is missing. @ line 97, column 21
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException

```