I am trying to work through the HelloWorld example on the Web that shows you how to create a build file using ANT in Eclipse. This is the project build file from the web example

 <?xml version="1.0" encoding="UTF-8"?>
 <project name="HW.makejar" default="makejar" basedir=".">
 	<target name="makejar" description="Create a jar for the HW project">
 		<jar jarfile="HelloWorld.jar" includes="*.class" basedir="."/>
 	</target>
 </project>

But when I run the resulting jar, I get this error message failed to load Main-Class manifest attribute from HelloWorld.jar. 

So then I tried it like this:

 <?xml version="1.0" encoding="UTF-8"?>
 <project name="HW.makejar" default="makejar" basedir=".">
 	<target name="makejar" description="Create a jar for the HW project">
 		<jar jarfile="HelloWorld.jar" includes="*.class" basedir=".">
 			<manifest>
 				<attribute name="Main-Class" value="ami.HelloWorld" />
 			</manifest>
 		</jar>
 
 	</target>
 </project>

When I reran the resulting jar, I got the following error message:

 Exception in thread "main" java.lang.NoClassDefFoundError: ami/HelloWorld

What am I doing wrong. By the way, when I manually compile the source and specify the Main.class within Eclipse, the resulting jar runs perfectly.