Program: 168118
Project: 168118
Buggy source:
/** 
 * Function to perform all the preprocessing steps on inFile
 * @param inFile File to be preprocessed
 * @param outName Optional field to define the temporary preprocessed file name. If this is empty, the temp file will have the same name as the inFile
 * @return
 */
private String processFile(String inFileBefore,String outName){
  String inFile=checkfiletype(inFileBefore);
  String outFile;
  if (outName == "String_Node_Str" || outName == null) {
    outFile=ppFilesLoc + System.getProperty("String_Node_Str") + (new File(inFile).getName());
  }
 else {
    outFile=ppFilesLoc + System.getProperty("String_Node_Str") + outName;
  }
  try {
    BufferedReader br=new BufferedReader(new FileReader(inFile));
    if (new File(outFile).exists()) {
      for (int i=1; i < Integer.MAX_VALUE; i++) {
        if (new File(outFile + Integer.toString(i)).exists()) {
          continue;
        }
 else {
          outFile=outFile + Integer.toString(i);
          break;
        }
      }
    }
    BufferedWriter bw=new BufferedWriter(new FileWriter(outFile));
    String currLine="String_Node_Str";
    while ((currLine=br.readLine()) != null) {
      if (currLine.trim().length() != 0) {
        if (doLowercase) {
          currLine=currLine.toLowerCase();
        }
        for (        char c : delimiters.toCharArray()) {
          currLine=currLine.replace(c,' ');
        }
        if (doStopWords) {
          currLine=removeStopWords(currLine);
        }
        if (doStemming) {
          if (isLatin) {
            try {
              currLine=latinStemmer.doStemming(currLine);
            }
 catch (            TreeTaggerException e) {
              ConsoleView.printlInConsole("String_Node_Str" + currLine);
              ConsoleView.printlInConsole("String_Node_Str");
            }
          }
 else {
            currLine=stemLine(currLine);
          }
        }
        bw.write(currLine + "String_Node_Str");
      }
    }
    bw.close();
    br.close();
  }
 catch (  FileNotFoundException e) {
    ConsoleView.printlInConsoleln("String_Node_Str" + inFile);
    return "String_Node_Str";
  }
catch (  IOException e) {
    ConsoleView.printlInConsoleln("String_Node_Str" + inFile);
  }
  return outFile;
}

Fixed version (ground truth):
/** 
 * Function to perform all the preprocessing steps on inFile
 * @param inFile File to be preprocessed
 * @param outName Optional field to define the temporary preprocessed file name. If this is empty, the temp file will have the same name as the inFile
 * @return
 * @throws TikaException 
 */
private String processFile(String inFileBefore,String outName) throws TikaException {
  String inFile=checkfiletype(inFileBefore);
  String outFile;
  if (outName == "String_Node_Str" || outName == null) {
    outFile=ppFilesLoc + System.getProperty("String_Node_Str") + (new File(inFile).getName());
  }
 else {
    outFile=ppFilesLoc + System.getProperty("String_Node_Str") + outName;
  }
  try {
    BufferedReader br=new BufferedReader(new FileReader(inFile));
    if (new File(outFile).exists()) {
      for (int i=1; i < Integer.MAX_VALUE; i++) {
        if (new File(outFile + Integer.toString(i)).exists()) {
          continue;
        }
 else {
          outFile=outFile + Integer.toString(i);
          break;
        }
      }
    }
    BufferedWriter bw=new BufferedWriter(new FileWriter(outFile));
    String currLine="String_Node_Str";
    while ((currLine=br.readLine()) != null) {
      if (currLine.trim().length() != 0) {
        if (doLowercase) {
          currLine=currLine.toLowerCase();
        }
        for (        char c : delimiters.toCharArray()) {
          currLine=currLine.replace(c,' ');
        }
        if (doStopWords) {
          currLine=removeStopWords(currLine);
        }
        if (doStemming) {
          if (isLatin) {
            try {
              currLine=latinStemmer.doStemming(currLine);
            }
 catch (            TreeTaggerException e) {
              ConsoleView.printlInConsole("String_Node_Str" + currLine);
              ConsoleView.printlInConsole("String_Node_Str");
            }
          }
 else {
            currLine=stemLine(currLine);
          }
        }
        bw.write(currLine + "String_Node_Str");
      }
    }
    bw.close();
    br.close();
  }
 catch (  FileNotFoundException e) {
    ConsoleView.printlInConsoleln("String_Node_Str" + inFile);
    return "String_Node_Str";
  }
catch (  IOException e) {
    ConsoleView.printlInConsoleln("String_Node_Str" + inFile);
  }
  return outFile;
}