* @param javaSource String containing Java source to parse
   * @return a CompilationUnitDeclaration or null if parsing failed
   */
  private static CompilationUnitDeclaration parseJava(String javaSource) {
    CodeSnippetParsingUtil parsingUtil = new CodeSnippetParsingUtil();
    CompilerOptions options = new CompilerOptions();
    options.complianceLevel = ClassFileConstants.JDK1_5;
    options.sourceLevel = ClassFileConstants.JDK1_5;
    CompilationUnitDeclaration unit = parsingUtil.parseCompilationUnit(
        javaSource.toString().toCharArray(), options.getMap(), true);
    if (unit.compilationResult().hasProblems()) {
      return null;
    }
    return unit;
  }