running jar file error:

[Aiping Zhou]

Hello,
I am new to ant. Thank in advance for any helps.
My problem is I can not run my java file "hello.class" by using the jar file construct by ant build.xml. However I can successfully run it by using my .class file directly.
The error message prompt by ant like this:

  
run:
     [java] java.lang.NoClassDefFoundError: hello
     [java] Exception in thread "main"
     [java] Java Result: 1

Here is my build.xml using my jar to run:

 <?xml version='1.0'?>
  <project name="HelloAnt" default="run" basedir="."> 
    
<!-- ============================== -->
<!--set global properties       -->
<!-- ============================== -->
    <property name="version" value="1.0"/>
    <property name="author" value="Aiping Zhou"/>
    <property name="title" value="Hello Ant"/>
    <property name="name" value="hello"/>
    <property name="run_class_name" value="Hello"/>
    <property name="jdk_version" value="1.4"/>
    <property name="src" value="src"/>
    <property name="lib"  value="lib"/>
    <property name="doc" value="mydocs"/>
    <property name="build"  value="myclass"/>
    <property name="data"  value="mydata"/>
    <property name="extra"  value="extra"/>


<!-- ========================= -->
<!--  Make directories       -->
<!-- ========================= -->
    <target name="init"> 
      <mkdir dir="${lib}" />
      <mkdir dir="${build}" />
      <mkdir dir="${doc}" />
      <mkdir dir="${data}" />
      <mkdir dir="${extra}" />
    </target>

<!-- ===================================== -->
<!--     Compile the java source tree      -->
<!-- ===================================== -->
<target name="compile" depends="init" >
<javac srcdir="${src}" 
   destdir="${build}" 
   fork="yes">   
<classpath>
   <pathelement path="${build}"/>
</classpath>
</javac>
</target>

<!-- ===================================================== -->
<!--jars a set of files & saved into jar directory     -->
<!-- ===================================================== -->
    <target name="jar" depends="compile"> 
      <jar jarfile="${lib}/${name}.jar" basedir="${build}" > 
        <include name="${build}/*.class"/>        
      </jar>
    </target>
<!-- ======================= -->
<!--Run this project     -->
<!-- ======================= -->
    <target name="run" depends="jar">
[B]
      <java classname="Hello" fork="true">
<classpath>
  <pathelement path="${build}"/>
        </classpath>
      </java>
[/B] 
    </target>
</project>
 

Hoever, it runs fine while I directly run the .class file under my "myclass" folder using the following code:

    
<!-- ========================= -->
<!--Run using .class file  -->
<!-- ========================= -->
    <target name="run" depends="jar">
[B]
<java classname="hello"
classpath="${lib}/${name}.jar"
fork="true"
/>
[/B] 
    </target>
 

Any one? Thanks again.
[ February 18, 2004: Message edited by: Aiping Zhou ]

[Tony Yan]

Make sure Hello is spelled right. Case Sensitivity problem?

[Aiping Zhou]

I tried both, the results are same.

[Tony Yan]

Not sure. First make sure that the jar file in ${build} does contain your hello.class file in the right path ( root if default-packaged). Then, may be trying some different format of java task, like this:
<java classname="test.Main">
<arg value="-h"/>
<classpath>
<pathelement location="dist/test.jar"/>
<pathelement path="${java.class.path}"/>
</classpath>
</java>