Help for javac task in ant?

Question

Here I have 5+ folders, ervery has many java source files. And all the java source files in these folders is the same package name, also there may have same file name in different folder. And now I want the javac to compile these files and save the classes file to each own folder.
folder--fd1
| |--a1.java (package org.apache.jsp)
| |--b1.java (package org.apache.jsp)
| |--c1.java (package org.apache.jsp)
|---fd2
| |--a1.java (same file name as in fd1) (package org.apache.jsp)
| |--b2.java (package org.apache.jsp)
| |--c2.java (package org.apache.jsp)
|--
foler--fd1
| |--a1.java
| |--a1.class (also the package is org.apache.jsp, but it store in here.)
| |--b1.java
| |--b1.class
| |--c1.java
| |--c1.class
|---fd2
| |--a1.java (same file name as in fd1)
| |--a1.class
| |--b2.java
| |--b2.class
| |--c2.java
| |--c2.class
|--
And now I can complete the compile work through 2 steps in up condition, first to compile fd1 folder, and then to compile fd2 folder. For if I just compile with folder(root folder), it will return duplicate class error. How could I do with this?
below is my javac config in build.xml:
<target name="compile" >
<path id="javac.classpath">
<fileset dir="${tomcat.home}\common\lib">
<include name="*.jar"/>
</fileset>
<fileset dir="${tomcat.home}\server\lib">
<include name="*.jar"/>
</fileset>
<pathelement location="${basedir}\classes" />
<fileset dir="${basedir}\web\WEB-INF\lib">
<include name="*.jar"/>
</fileset>
</path>
<javac failonerror="true" debug="off" verbose="2" deprecation="off" classpathref="javac.classpath">               
<src path="${basedir}/folder/fd1"/>                         
</javac>          
<javac failonerror="false" debug="off" verbose="2" deprecation="off" classpathref="javac.classpath">               
<src path="${basedir}/folder/fd1"/>                         
</javac>
</target>

Answer 1

But the problem is that this project may have same
e files in 5 folders, and another may more than 5,
like 20+, then also step to compile it, I think it can
not imagine.As I said, the basic problem is that the class path has to be different for each folder.
So what I want is just compile once, and is there
e any solution to escape the duplicate class error.
And the jikes compile you refered, I don't know how
w to call this task, for jikes is just a binary
file.(how to set parameter in <javac/> in build.xml
used by ant)
Jikes is a compiler from IBM. If you look in the ant docs it tells you how to set it up.