在整理springboot的基本架构时，某一个层在build的时候发生了如下异常：

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building entity 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[WARNING] The POM for org.hibernate:hibernate-validator:jar:5.3.4.Final is invalid, transitive dependencies (if any) will not be available, enable debug logging for more details
[WARNING] The POM for log4j:log4j:jar:1.2.16 is invalid, transitive dependencies (if any) will not be available, enable debug logging for more details
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ entity ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ entity ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ entity ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/nemo/workspace/trunk/entity/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ entity ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-surefire-plugin:2.18.1:test (default-test) @ entity ---
[INFO] No tests to run.
[INFO] 
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ entity ---
[INFO] 
[INFO] --- spring-boot-maven-plugin:1.5.2.RELEASE:repackage (default) @ entity ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.393 s
[INFO] Finished at: 2017-03-20T19:37:22+08:00
[INFO] Final Memory: 27M/347M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:1.5.2.RELEASE:repackage (default) on project entity: Execution default of goal org.springframework.boot:spring-boot-maven-plugin:1.5.2.RELEASE:repackage failed: Unable to find main class -> [Help 1]
[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/PluginExecutionException

异常提示找不到main方法。

遂在该module的根包下新建了一个MailMudule.java,其中添加了main方法...

问题就没了。

暂时不明所以，先记录下来。。