title: Why is Maven downloading the maven-metadata.xml every time?
body: <p>Below is the error I usually get when my internet connection is flanky when trying to build a web application with maven. </p>
  
  <p>My question is that, why does maven always have to download every time when the same app has been built earlier. </p>
  
  <p>What could be wrong in my configuration that makes maven to download every time? </p>
  
  <p>Below is an error I get when I try to build offline: </p>
  
  <pre><code>[INFO] ------------------------------------------------------------------------
  [INFO] Building mywebapp 1.0-SNAPSHOT
  [INFO] ------------------------------------------------------------------------
  Downloading: https://raw.github.com/pagecrumb/mungo/mvn-repo/com/pagecrumb/mungo/0.0.1-SNAPSHOT/maven-metadata.xml
  
  [WARNING] Could not transfer metadata com.mywebapp:mungo:0.0.1-SNAPSHOT/maven-metadata.xml 
  from/to mungo-mvn-repo (https://raw.github.com/pagecrumb/mungo/mvn-repo/): raw.github.com
  [INFO] 
  [INFO] --- maven-war-plugin:2.1.1:war (default-cli) @ mywebapp ---
  [INFO] Packaging webapp
  [INFO] Assembling webapp [mywebapp] in [D:\workspace\web\target\mywebapp-1.0-SNAPSHOT]
  [INFO] Processing war project
  [INFO] Copying webapp resources [D:\workspace\web\src\main\webapp]
  [INFO] Webapp assembled in [1237 msecs]
  [INFO] Building war: D:\workspace\web\target\mywebapp-1.0-SNAPSHOT.war
  [WARNING] Warning: selected war files include a WEB-INF/web.xml which will be ignored 
  (webxml attribute is missing from war task, 
  or ignoreWebxml attribute is specified as 'true')
  [INFO]                                                                         
  [INFO] ------------------------------------------------------------------------
  [INFO] Building com.mywebapp [com.mywebapp] 0.0.1-SNAPSHOT
  [INFO] ------------------------------------------------------------------------
  Downloading: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-release-plugin/2.1/maven-release-plugin-2.1.pom
  
  [WARNING] Failed to retrieve plugin descriptor for org.apache.maven.plugins:maven-release-plugin:2.1: Plugin org.apache.maven.plugins:maven-release-plugin:2.1 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-release-plugin:jar:2.1
  Downloading: http://download.java.net/maven/2/org/apache/maven/plugins/maven-metadata.xml
  Downloading: http://download.java.net/maven/2/org/codehaus/mojo/maven-metadata.xml
  
  397/397 B   
  
  Downloaded: http://download.java.net/maven/2/org/codehaus/mojo/maven-metadata.xml (397 B at 0.0 KB/sec)
  [WARNING] Failure to transfer org.apache.maven.plugins:maven-war-plugin/maven-metadata.xml from http://download.java.net/maven/2 was cached in the local repository, resolution will not be reattempted until the update interval of maven2-repository.dev.java.net has elapsed or updates are forced. Original error: Could not transfer metadata org.apache.maven.plugins:maven-war-plugin/maven-metadata.xml from/to maven2-repository.dev.java.net (http://download.java.net/maven/2): download.java.net
  [INFO] 
  [INFO] --- maven-war-plugin:2.3:war (default-cli) @ mywebapp-build ---
  [INFO] Packaging webapp
  [INFO] Assembling webapp [mywebapp-build] in [D:\workspace\target\mywebapp-build-0.0.1-SNAPSHOT]
  [INFO] Processing war project
  [INFO] Webapp assembled in [15 msecs]
  [INFO] Building war: D:\workspace\target\mywebapp-build-0.0.1-SNAPSHOT.war
  [INFO] ------------------------------------------------------------------------
  [INFO] Reactor Summary:
  [INFO] 
  [INFO] mywebapp ..................................... SUCCESS [27.999s]
  [INFO] com.mywebapp [com.mywebapp] ..................... FAILURE [1:00.406s]
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 1:41.409s
  [INFO] Finished at: Tue May 07 22:13:38 SGT 2013
  [INFO] Final Memory: 11M/28M
  [INFO] ------------------------------------------------------------------------
  [ERROR] Failed to execute goal org.apache.maven.plugins:maven-war-plugin:2.3:war 
  (default-cli) on project mywebapp-build: Error assembling WAR: webxml attribute is required (or pre-existing WEB-INF/web.xml if executing in update mode)
  </code></pre>