Using JavaCompiler in a Servlet

Question

Currently I am developing a tool in which Java Source Files are created based on a XSD file with help of a tool named Castor.
After the generation of the files the files need to be compiled in order to be used by the program. This used to be done with a Library named XMLBean, however I do not wish to use this library anymore.
As a alternative I ended up using the Java compiler that comes with the JDK in the tools.jar file. This resulted in a problem, which made me search for a other solution. This way I ended up working with the javax.tools.JavaCompiler. However compilation still failed due to the same problem.
So what is this problem?
Initially I tested my code generation logic and compile logic in a normal application. The Java code got generated fine using castor, the compilation using both methods I described also went fine.
The problem occurs when I attempt to use the same logic in a web application (Behind a servlet) I am developing to run on Tomcat. The Code generation goes fine (since the castor library is included in the project) however the compilation goes wrong and results in the following error:
"package org.exolab.castor.xml does not exist"
In other words, the compiler does not understand one of the imports of the source file (refering to a namespace in Castor, a library that was used to generate the file, and is included in the web project).
Does anyone know why compilation fails in a web application but goes well in a normal application? Does anyone know how this problem can be solved, or does anyone know better component for compilation?
Thanks a lot.
This is the code I currently use for compilation:
public void compileJavaSource(String[] sourceFilePaths)
          System.out.println("Begin Compiling of Source Files");
          JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); // Line 1.
          DiagnosticCollector<JavaFileObject> diagnosticsCollector = new DiagnosticCollector<JavaFileObject>();
          StandardJavaFileManager fileManager  = compiler.getStandardFileManager(diagnosticsCollector, null, null); // Line 3.
          Iterable<? extends JavaFileObject> fileObjects = fileManager.getJavaFileObjectsFromStrings(Arrays.asList(sourceFilePaths)); // Line 5
          CompilationTask task = compiler.getTask(null, fileManager, diagnosticsCollector, null, null, fileObjects); // Line 6
          Boolean result = task.call(); // Line 7
          List<Diagnostic<? extends JavaFileObject>> diagnostics = diagnosticsCollector.getDiagnostics();
          for(int i=0; i < diagnostics.size(); i++){
               Diagnostic<? extends JavaFileObject> d = diagnostics.get(i);
               System.out.println(d.getMessage(null));
          if(result == true) {
               System.out.println("Compilation has succeeded");
          else {
               System.out.println("Compilation fails.");
          System.out.println("Done Compiling of Source Files");
     } Initially I used this:
com.sun.tools.javac.Main.compile(sourceFilePaths);

Answer 1

Cross posted. (Sorry about that)
To avoid people spending time looking for an answer, here is the solution I found myself:
First off all, for ANT to work, 2 libraries have to be imported in the web project.
The libraries are: ant.jar and ant-launcher.jar
Next to that, the library's Xerces (xercesImpl.jar) and xml-apis.jar (also included in ANT). There Library's are also needed to get Castor to work.
To compile the code of my generated Java Classes I use the following ANT Build file code:
<project default="build" basedir=".">
     <path id="classpath">
        <fileset dir="WEB-INF/lib" includes="**/*.jar"/>
    </path>
     <target name="build">
        <javac srcdir="src" destdir="WEB-INF/classes" debug="true" includes="**/*.java" classpathref="classpath"/>
     </target>
</project>The file basically reads every .java file from my "src" folder. Which is the folder I choose to put my generated class files, and compiles them to the WEB-INF/classes folder. This is the folder were Tomcat stores all its classes.
What went wrong with the compilation I attempted in the opening post, is that javac could not find the Castor Library, even after I added it in my classpath environment variable. Fortunately, with ANT I can define a classpath for the application, which is the WEB-INF/lib folder. This is the folder where Tomcat stores its Library's. Hence, javac can find the Castor Library from then on.
Finally I call the ant task using the following Java Code:
public void compileJavaSource(String buildFilePath)
          System.out.println("Start Compilation");
          File buildFile = new File(buildFilePath);
          Project p = new Project();
          p.setUserProperty("ant.file", buildFilePath);
          p.init();
          ProjectHelper helper = ProjectHelper.getProjectHelper();
          p.addReference("ant.projectHelper", helper);
          helper.parse(p, buildFile);
          p.executeTarget(p.getDefaultTarget());
          System.out.println("Compilation Finished");
     }This took care of the problem pretty nicely.