Program: 3110
Project: 3110
Buggy source:
public void print(PrintWriter out){
  if (data != null) {
    for (    Object[] dataRow : data) {
      Object[] printRow=dataRow.clone();
      for (int i=0; i < printRow.length; i++) {
        if (printRow[i] == null) {
          printRow[i]="String_Node_Str";
        }
        if (printRow[i] instanceof HistogramData) {
          StringWriter buffer=new StringWriter();
          PrintWriter writer=new PrintWriter(buffer);
          ((HistogramData)printRow[i]).print(writer);
          writer.flush();
          printRow[i]=buffer.toString();
        }
        if (printRow[i] instanceof String) {
          String value=(String)printRow[i];
          if (value.contains("String_Node_Str")) {
            printRow[i]=reformatMultilineValue(value);
          }
        }
      }
      String usedFormat=this.format;
      if (usedFormat == null) {
        if (name != null && !name.equals("String_Node_Str")) {
          out.println(name);
        }
        StringBuilder buffer=new StringBuilder();
        for (int i=0; i < printRow.length; i++) {
          buffer.append("String_Node_Str");
          buffer.append(getFormat(printRow[i]));
        }
        usedFormat=buffer.toString();
      }
 else {
        Matcher m=INDEX_PATTERN.matcher(usedFormat);
        int maxIndex=-1;
        int minIndex=Integer.MAX_VALUE;
        while (m.find()) {
          int index=Integer.valueOf(m.group(1)).intValue();
          if (index > maxIndex) {
            maxIndex=index;
          }
          if (index < minIndex) {
            minIndex=index;
          }
        }
        Object[] titledRow=new Object[printRow.length + 1];
        System.arraycopy(printRow,0,titledRow,0,printRow.length);
        titledRow[printRow.length]=name;
        usedFormat=minIndex > 0 ? getFormat(titledRow[printRow.length]).replace("String_Node_Str","String_Node_Str" + (maxIndex + 1) + "String_Node_Str") + "String_Node_Str" + usedFormat : usedFormat.replace("String_Node_Str","String_Node_Str" + titledRow.length + "String_Node_Str");
        printRow=titledRow;
      }
      String line=String.format(usedFormat,printRow);
      out.println(line);
    }
  }
}

Fixed version (ground truth):
public void print(PrintWriter out){
  System.err.println("String_Node_Str" + (data != null));
  if (data != null) {
    if (name != null && !name.equals("String_Node_Str")) {
      out.println(name);
    }
    for (    Object[] dataRow : data) {
      Object[] printRow=dataRow.clone();
      for (int i=0; i < printRow.length; i++) {
        if (printRow[i] == null) {
          printRow[i]="String_Node_Str";
        }
        if (printRow[i] instanceof HistogramData) {
          StringWriter buffer=new StringWriter();
          PrintWriter writer=new PrintWriter(buffer);
          ((HistogramData)printRow[i]).print(writer);
          writer.flush();
          printRow[i]=buffer.toString();
        }
        if (printRow[i] instanceof String) {
          String value=(String)printRow[i];
          if (value.contains("String_Node_Str")) {
            printRow[i]=reformatMultilineValue(value);
          }
        }
      }
      String usedFormat=this.format;
      System.err.println("String_Node_Str" + usedFormat);
      if (usedFormat == null || usedFormat.length() == 0) {
        StringBuilder buffer=new StringBuilder();
        for (int i=0; i < printRow.length; i++) {
          buffer.append("String_Node_Str");
          buffer.append(getFormat(printRow[i]));
        }
        usedFormat=buffer.toString();
      }
      String line=String.format(usedFormat,printRow);
      out.println(line);
    }
  }
}