title: eclipse on maven project warning 'DTD or XML schema'
body: <pre><code>Description Resource    Path    Location    Type
  No grammar constraints (DTD or XML schema) detected for the document.   TEST-net.kindleit.gae.example.server.MessageRepositoryTest.xml  /projecttest-gae-example/target/surefire-reports    line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   appengine-web.xml   /projecttest-gae-example/src/main/webapp/WEB-INF    line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   appengine-web.xml   /projecttest-gae-example/target/projecttest-gae-example-1.0-SNAPSHOT/WEB-INF    line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   datastore-indexes-auto.xml  /projecttest-gae-example/WEB-INF/appengine-generated    line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   jdoconfig.xml   /projecttest-gae-example/src/main/resources/META-INF    line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   jdoconfig.xml   /projecttest-gae-example/target/projecttest-gae-example-1.0-SNAPSHOT/WEB-INF/classes/META-INF   line 1  XML Problem
  No grammar constraints (DTD or XML schema) detected for the document.   webapp-cache.xml    /projecttest-gae-example/target/war/work    line 1  XML Problem
  </code></pre>
  
  <p>how to fix the above problem on eclipse? my project is maven based. Is it because I miss out some dtd files? how to include it?</p>
  
  <p>example jdoconfig.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;jdoconfig xmlns="http://java.sun.com/xml/ns/jdo/jdoconfig"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:noNamespaceSchemaLocation="http://java.sun.com/xml/ns/jdo/jdoconfig"&gt;
  
      &lt;persistence-manager-factory name="transactions-optional"&gt;
          &lt;property name="javax.jdo.PersistenceManagerFactoryClass"
              value="org.datanucleus.store.appengine.jdo.DatastoreJDOPersistenceManagerFactory"/&gt;
          &lt;property name="javax.jdo.option.ConnectionURL" value="appengine"/&gt;
          &lt;property name="javax.jdo.option.NontransactionalRead" value="true"/&gt;
          &lt;property name="javax.jdo.option.NontransactionalWrite" value="true"/&gt;
          &lt;property name="javax.jdo.option.RetainValues" value="true"/&gt;
          &lt;property name="datanucleus.appengine.autoCreateDatastoreTxns" value="true"/&gt;
      &lt;/persistence-manager-factory&gt;
  &lt;/jdoconfig&gt;
  </code></pre>