Use Java 5 to illustrate annotation support.

samples/tutorial/pom.xml

@@ -56,6 +56,14 @@
 
     <build>
         <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>1.5</source>
+          <target>1.5</target>
+        </configuration>
+      </plugin>
             <plugin>
                 <groupId>org.mortbay.jetty</groupId>
                 <artifactId>maven-jetty-plugin</artifactId>