Program: 168244
Project: 168244
Buggy source:
public int doPreprocess() throws IOException, LangDetectException {
  if (stopwordsFile != null && !stopwordsFile.isEmpty()) {
    File sFile=new File(stopwordsFile);
    if (!sFile.exists() || sFile.isDirectory()) {
      System.out.println("String_Node_Str" + sFile.getAbsolutePath());
      appendLog("String_Node_Str" + sFile.getAbsolutePath());
      return -2;
    }
 else {
      doStopWords=true;
      String currentLine;
      BufferedReader br=new BufferedReader(new FileReader(sFile));
      while ((currentLine=br.readLine()) != null) {
        stopWordsSet.add(currentLine.trim().toLowerCase());
      }
      br.close();
    }
  }
  if (doStemming) {
    if (stemLang.equals("String_Node_Str")) {
      appendLog("String_Node_Str");
      doLangDetect=true;
      System.out.println(System.getProperty("String_Node_Str"));
      System.out.println(this.getClass().getResource("String_Node_Str").getPath());
      try {
        DetectorFactory.loadProfile("String_Node_Str");
      }
 catch (      com.cybozu.labs.langdetect.LangDetectException ex) {
        System.out.println("String_Node_Str" + ex.getCode());
      }
    }
 else {
      doLangDetect=false;
      stemmer=stemSelect(stemLang);
    }
  }
  for (  String inputFile : inputFiles) {
    System.out.println("String_Node_Str" + inputFile);
    appendLog("String_Node_Str" + inputFile);
    File iFile=new File(inputFile);
    if (!iFile.exists() || iFile.isDirectory()) {
      System.out.println("String_Node_Str" + iFile.getAbsolutePath());
      appendLog("String_Node_Str" + iFile.getAbsolutePath());
      return -1;
    }
    int dindex=inputFile.lastIndexOf('.');
    int findex=inputFile.lastIndexOf('\\');
    String fname=inputFile.substring(findex,dindex);
    String ext=inputFile.substring(dindex + 1);
    File oFile=new File(outputPath + "String_Node_Str" + fname+ suffix+ "String_Node_Str"+ ext);
    System.out.println("String_Node_Str" + oFile.getAbsolutePath());
    appendLog("String_Node_Str" + oFile.getAbsolutePath());
    if (doLangDetect) {
      stemmer=findLangStemmer(iFile);
      if (stemmer == null) {
        appendLog("String_Node_Str");
        return -3;
      }
    }
    BufferedReader br=new BufferedReader(new FileReader(iFile));
    BufferedWriter bw=new BufferedWriter(new FileWriter(oFile));
    String currentLine;
    while ((currentLine=br.readLine()) != null) {
      for (      char c : delimiters.toCharArray())       currentLine=currentLine.replace(c,' ');
      if (doLowercase)       currentLine=currentLine.toLowerCase();
      if (doStopWords)       currentLine=removeStopWords(currentLine);
      if (doStemming)       currentLine=stem(currentLine);
      bw.write(currentLine);
      bw.newLine();
    }
    br.close();
    bw.close();
  }
  return 1;
}

Fixed version (ground truth):
public int doPreprocess() throws IOException, LangDetectException {
  if (stopwordsFile != null && !stopwordsFile.isEmpty()) {
    File sFile=new File(stopwordsFile);
    if (!sFile.exists() || sFile.isDirectory()) {
      System.out.println("String_Node_Str" + sFile.getAbsolutePath());
      appendLog("String_Node_Str" + sFile.getAbsolutePath());
      return -2;
    }
 else {
      doStopWords=true;
      String currentLine;
      BufferedReader br=new BufferedReader(new FileReader(sFile));
      while ((currentLine=br.readLine()) != null) {
        stopWordsSet.add(currentLine.trim().toLowerCase());
      }
      br.close();
    }
  }
  if (doStemming) {
    if (stemLang.equals("String_Node_Str")) {
      appendLog("String_Node_Str");
      doLangDetect=true;
      System.out.println(System.getProperty("String_Node_Str"));
      System.out.println(this.getClass().getResource("String_Node_Str").getPath());
      try {
        DetectorFactory.loadProfile("String_Node_Str");
      }
 catch (      com.cybozu.labs.langdetect.LangDetectException ex) {
        System.out.println("String_Node_Str" + ex.getCode());
      }
    }
 else {
      doLangDetect=false;
      stemmer=stemSelect(stemLang);
    }
  }
  for (  String inputFile : inputFiles) {
    System.out.println("String_Node_Str" + inputFile);
    appendLog("String_Node_Str" + inputFile);
    File iFile=new File(inputFile);
    if (!iFile.exists() || iFile.isDirectory()) {
      System.out.println("String_Node_Str" + iFile.getAbsolutePath());
      appendLog("String_Node_Str" + iFile.getAbsolutePath());
      return -1;
    }
    int dindex=inputFile.lastIndexOf('.');
    int findex=inputFile.lastIndexOf(System.getProperty("String_Node_Str"));
    String fname=inputFile.substring(findex,dindex);
    String ext=inputFile.substring(dindex + 1);
    File oFile=new File(outputPath + System.getProperty("String_Node_Str") + fname+ suffix+ "String_Node_Str"+ ext);
    System.out.println("String_Node_Str" + oFile.getAbsolutePath());
    appendLog("String_Node_Str" + oFile.getAbsolutePath());
    if (doLangDetect) {
      stemmer=findLangStemmer(iFile);
      if (stemmer == null) {
        appendLog("String_Node_Str");
        return -3;
      }
    }
    BufferedReader br=new BufferedReader(new FileReader(iFile));
    BufferedWriter bw=new BufferedWriter(new FileWriter(oFile));
    String currentLine;
    while ((currentLine=br.readLine()) != null) {
      for (      char c : delimiters.toCharArray())       currentLine=currentLine.replace(c,' ');
      if (doLowercase)       currentLine=currentLine.toLowerCase();
      if (doStopWords)       currentLine=removeStopWords(currentLine);
      if (doStemming)       currentLine=stem(currentLine);
      bw.write(currentLine);
      bw.newLine();
    }
    br.close();
    bw.close();
  }
  return 1;
}