Program: 168239
Project: 168239
Buggy source:
public String doPreprocessing(String path) throws IOException {
  File[] files;
  File input=new File(path);
  String outputPath;
  if (input.isDirectory()) {
    files=input.listFiles();
    outputPath=path + System.getProperty("String_Node_Str") + "String_Node_Str";
  }
 else {
    files=new File[1];
    files[0]=input;
    outputPath=input.getParentFile().getAbsolutePath() + System.getProperty("String_Node_Str") + "String_Node_Str";
  }
  if (new File(outputPath).mkdir()) {
    System.out.println("String_Node_Str");
  }
  if (options.getStopFile() != null && options.getStopFile() != "String_Node_Str" && options.getStopFile().length() > 3) {
    doStopWords=true;
    String currentLine;
    BufferedReader br=new BufferedReader(new FileReader(new File(options.getStopFile())));
    while ((currentLine=br.readLine()) != null) {
      stopWordsSet.add(currentLine.trim().toLowerCase());
    }
    br.close();
  }
  if (options.isDoStemming()) {
    if (options.getStemLang().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(options.getStemLang());
    }
  }
  for (  File f : files) {
    if ("String_Node_Str".equals(f.getName()))     continue;
    String inputFile=f.getAbsolutePath();
    System.out.println("String_Node_Str" + inputFile);
    if (doLangDetect) {
      try {
        stemmer=findLangStemmer(f);
      }
 catch (      LangDetectException e) {
        e.printStackTrace();
      }
      if (stemmer == null) {
        appendLog("String_Node_Str");
      }
    }
    File iFile=new File(inputFile);
    if (!iFile.exists() || iFile.isDirectory()) {
      System.out.println("String_Node_Str" + iFile.getAbsolutePath());
      appendLog("String_Node_Str" + iFile.getAbsolutePath());
      continue;
    }
    File oFile=new File(outputPath + System.getProperty("String_Node_Str") + f.getName());
    BufferedReader br=new BufferedReader(new FileReader(iFile));
    BufferedWriter bw=new BufferedWriter(new FileWriter(oFile));
    String linear;
    while ((linear=br.readLine()) != null) {
      if (linear != "String_Node_Str") {
        if (options.isDoLowercase())         linear=linear.toLowerCase();
        for (        char c : options.getDelimiters().toCharArray())         linear=linear.replace(c,' ');
        if (doStopWords)         linear=removeStopWords(linear);
        if (options.isDoStemming())         linear=stem(linear);
        bw.write(linear + "String_Node_Str");
      }
    }
    System.out.println(outputPath + System.getProperty("String_Node_Str") + f.getName());
    br.close();
    bw.close();
  }
  System.out.println("String_Node_Str" + outputPath);
  return outputPath;
}

Fixed version (ground truth):
public String doPreprocessing(String path) throws IOException {
  File[] files;
  File input=new File(path);
  String outputPath;
  if (input.isDirectory()) {
    files=input.listFiles();
    outputPath=path + System.getProperty("String_Node_Str") + "String_Node_Str";
  }
 else {
    files=new File[1];
    files[0]=input;
    outputPath=input.getParentFile().getAbsolutePath() + System.getProperty("String_Node_Str") + "String_Node_Str";
  }
  if (new File(outputPath).mkdir()) {
    System.out.println("String_Node_Str");
  }
  if (options.getStopFile() != null && options.getStopFile() != "String_Node_Str" && options.getStopFile().length() > 3) {
    doStopWords=true;
    String currentLine;
    BufferedReader br=new BufferedReader(new FileReader(new File(options.getStopFile())));
    while ((currentLine=br.readLine()) != null) {
      stopWordsSet.add(currentLine.trim().toLowerCase());
    }
    br.close();
  }
  if (options.isDoStemming()) {
    if (options.getStemLang().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(options.getStemLang());
    }
  }
  for (  File f : files) {
    if ("String_Node_Str".equals(f.getName()))     continue;
    String inputFile=f.getAbsolutePath();
    System.out.println("String_Node_Str" + inputFile);
    if (doLangDetect) {
      try {
        stemmer=findLangStemmer(f);
      }
 catch (      LangDetectException e) {
        e.printStackTrace();
      }
      if (stemmer == null) {
        appendLog("String_Node_Str");
      }
    }
    File iFile=new File(inputFile);
    if (!iFile.exists() || iFile.isDirectory()) {
      System.out.println("String_Node_Str" + iFile.getAbsolutePath());
      appendLog("String_Node_Str" + iFile.getAbsolutePath());
      continue;
    }
    File oFile=new File(outputPath + System.getProperty("String_Node_Str") + f.getName());
    BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(iFile),"String_Node_Str"));
    BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream(oFile),"String_Node_Str"));
    String linear;
    while ((linear=br.readLine()) != null) {
      if (linear != "String_Node_Str") {
        if (options.isDoLowercase())         linear=linear.toLowerCase();
        for (        char c : options.getDelimiters().toCharArray())         linear=linear.replace(c,' ');
        if (doStopWords)         linear=removeStopWords(linear);
        if (options.isDoStemming())         linear=stem(linear);
        bw.write(linear + "String_Node_Str");
      }
    }
    System.out.println(outputPath + System.getProperty("String_Node_Str") + f.getName());
    br.close();
    bw.close();
  }
  System.out.println("String_Node_Str" + outputPath);
  return outputPath;
}