I have an Ant `build.xml` file that works just fine on the command line: it compiles, builds the JAR, and I am able to execute the main method from the JAR just fine. The `build.xml` file references several thirdparty libraries that are scattered here and there. When building the JAR, the script doesn't include all the thirdparty libraries into the JAR itself. Instead, it puts their path into the JAR's manifest. This helps to keep my JAR slim and tidy.

I'd like to be able to edit and debug my project in Eclipse, but I can't find an easy way to do so. I can have my project use the Ant file to build the project, and that seems to work. However, Eclipse is having trouble finding the thirdparty libaries, and thus Eclipse is having two problems: 

1. it shows (in the text editor) lots of compile errors, because
lots of classes are undefined, and
2. it can't execute the JAR.

I can solve both of the above problems by specifying by hand, in two difference places (i.e., the build path via `Properties->Java Build Path->Libraries`, and the execution classpath via `Run Configurations->Classpath`), all the third party libraries. But it seems like I shouldn't have to do this manually, since all the third party libraries are already listed in my JAR's manifest. What am I doing wrong?

Here's my `build.xml` file:

```
<!-- Set global properties for this build -->
<property name="src"         location="./src" />
<property name="build"       location="./build"/>
<property name="dist"        location="./dist"/>
<property name="logs"        location="./logs"/>
<property name="docs"        location="./docs"/>
<property name="jar"         location="${dist}/dynamic_analyzer.jar"/>
<property name="lib"         location="../../thirdparty/lib"/>
<property name="hive-util"   location="../../hive-utils/dist"/>
<property name="hpdb"        location="../../hive-db/hpdb/dist"/>
<property name="static"      location="../../hive-backend/static_analyzer/dist"/>
<property name="mainclass"   value="com.datawarellc.main.DynamicMain"/>

<path id="dep.runtime">
    <fileset dir="${lib}"       includes="**/*.jar"/>
    <fileset dir="${hive-util}" includes="**/*.jar"/>
    <fileset dir="${hpdb}"      includes="**/*.jar"/>
    <fileset dir="${static}"    includes="**/*.jar"/>
</path>

<target name="clean">
    <delete dir="${build}"/>
    <delete dir="${dist}"/>
    <delete dir="${docs}"/>
    <delete dir="${logs}"/>
</target>

<target name="init">
    <tstamp/>
    <mkdir dir="${build}"/>
    <mkdir dir="${dist}"/>
    <mkdir dir="${logs}"/>
</target>

<target name="compile" depends="init">
    <javac srcdir="${src}" destdir="${build}" debug="on" includeantruntime="false">
        <classpath refid="dep.runtime" />
    </javac>

    <!-- Debug output of classpath -->
    <property name="myclasspath" refid="dep.runtime"/>
    <echo message="Classpath = ${myclasspath}"/>

</target>

<target name="jar" depends="compile">
    <!-- Put the classpath in the manifest -->
    <manifestclasspath property="manifest_cp" jarfile="${jar}" maxParentLevels="10">
        <classpath refid="dep.runtime" />
    </manifestclasspath>

    <jar jarfile="${jar}" basedir="${build}">
        <manifest>
            <attribute name="Main-Class" value="${mainclass}"/>
            <attribute name="Class-Path" value="${manifest_cp}"/>
        </manifest>
        <zipfileset dir="${src}" includes="**/*.xml" />
    </jar>
</target>

```

You can see that I have third-party libraries in several directories (`${lib}`, `${hive-util}`, `${hpdb}`, and `${static}`). I use these to create a `path` called `dep.runtime`. I then include `dep.runtime` in the manifest when building my jar. **How can I get Eclipse to use the same `dep.runtime` for the build path and the classpath when executing?**