Program: 118925
Project: 118925
Buggy source:
protected String getNeededModulesJarStr(){
  final boolean exportingJob=ProcessorUtilities.isExportConfig();
  final String classPathSeparator=extractClassPathSeparator();
  final String libPrefixPath=getRootWorkingDir(true);
  final File libDir=JavaProcessorUtilities.getJavaProjectLibFolder();
  if (libDir == null) {
    return "String_Node_Str";
  }
  Set<ModuleNeeded> neededModules=getNeededModules();
  JavaProcessorUtilities.checkJavaProjectLib(neededModules);
  Set<String> neededLibraries=new HashSet<String>();
  for (  ModuleNeeded neededModule : neededModules) {
    neededLibraries.add(neededModule.getModuleName());
  }
  File[] jarFiles=libDir.listFiles(FilesUtils.getAcceptJARFilesFilter());
  StringBuffer libPath=new StringBuffer();
  if (jarFiles != null && jarFiles.length > 0) {
    for (    File jarFile : jarFiles) {
      if (jarFile.isFile() && neededLibraries.contains(jarFile.getName())) {
        String singleLibPath=new Path(jarFile.getAbsolutePath()).toPortableString();
        if (exportingJob) {
          libPath.append(libPrefixPath);
          singleLibPath=singleLibPath.replace(new Path(libDir.getAbsolutePath()).toPortableString(),getBaseLibPath());
        }
        libPath.append(singleLibPath).append(classPathSeparator);
      }
    }
  }
  final int lastSep=libPath.length() - 1;
  if (libPath.length() != 0 && classPathSeparator.equals(String.valueOf(libPath.charAt(lastSep)))) {
    libPath.deleteCharAt(lastSep);
  }
  return libPath.toString();
}

Fixed version (ground truth):
protected String getNeededModulesJarStr(){
  final String classPathSeparator=extractClassPathSeparator();
  final String libPrefixPath=getRootWorkingDir(true);
  Set<ModuleNeeded> neededModules=getNeededModules();
  JavaProcessorUtilities.checkJavaProjectLib(neededModules);
  StringBuffer libPath=new StringBuffer();
  if (isExportConfig() || isRunAsExport()) {
    boolean hasLibPrefix=libPrefixPath.length() > 0;
    for (    ModuleNeeded neededModule : neededModules) {
      if (hasLibPrefix) {
        libPath.append(libPrefixPath);
      }
      libPath.append(getBaseLibPath());
      libPath.append(JavaUtils.PATH_SEPARATOR);
      libPath.append(neededModule.getModuleName());
      libPath.append(classPathSeparator);
    }
  }
 else {
    Set<String> neededLibraries=new HashSet<String>();
    for (    ModuleNeeded neededModule : neededModules) {
      neededLibraries.add(neededModule.getModuleName());
    }
    final File libDir=JavaProcessorUtilities.getJavaProjectLibFolder();
    if (libDir == null) {
      return "String_Node_Str";
    }
    File[] jarFiles=libDir.listFiles(FilesUtils.getAcceptJARFilesFilter());
    if (jarFiles != null && jarFiles.length > 0) {
      for (      File jarFile : jarFiles) {
        if (jarFile.isFile() && neededLibraries.contains(jarFile.getName())) {
          String singleLibPath=new Path(jarFile.getAbsolutePath()).toPortableString();
          libPath.append(singleLibPath).append(classPathSeparator);
        }
      }
    }
  }
  final int lastSep=libPath.length() - 1;
  if (libPath.length() != 0 && classPathSeparator.equals(String.valueOf(libPath.charAt(lastSep)))) {
    libPath.deleteCharAt(lastSep);
  }
  return libPath.toString();
}