title: Getting warning dependencies dependency while running mvn install clean command
body: <pre><code>[INFO] Scanning for projects...
  [WARNING] 
  [WARNING] Some problems were encountered while building the effective model for com.coexi.appi:appi-core:jar:0.0.3-SNAPSHOT
  [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 190, column 12
  [WARNING] 
  [WARNING] Some problems were encountered while building the effective model for com.coexi.appi:appi-gc:jar:0.0.3-SNAPSHOT
  [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 197, column 12
  [WARNING] 
  [WARNING] Some problems were encountered while building the effective model for com.coexi.appi:appi-eshop:jar:0.0.3-SNAPSHOT
  [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 36, column 12
  [WARNING] 
  [WARNING] Some problems were encountered while building the effective model for com.coexi.appi:appi-front-jsf:jar:0.0.4-SNAPSHOT
  [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 59, column 12
  [WARNING] 
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-context:jar -&gt; duplicate declaration of version ${spring.version} @ line 69, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-context:jar -&gt; duplicate declaration of version ${spring.version} @ line 81, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-web:jar -&gt; duplicate declaration of version ${spring.version} @ line 87, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-web:jar -&gt; duplicate declaration of version ${spring.version} @ line 99, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-tx:jar -&gt; duplicate declaration of version ${spring.version} @ line 105, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework:spring-tx:jar -&gt; duplicate declaration of version ${spring.version} @ line 113, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework.security:spring-security-web:jar -&gt; duplicate declaration of version ${spring.security.version} @ line 162, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework.security:spring-security-web:jar -&gt; duplicate declaration of version ${spring.security.version} @ line 174, column 15
  [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework.security:spring-security-config:jar -&gt; duplicate declaration of version ${spring.security.version} @ line 180, column 15
  [WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 500, column 12
  [WARNING] 
  [WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
  [WARNING] 
  [WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
  [WARNING] 
  </code></pre>