Program: 42789
Project: 42789
Buggy source:
public static void main(String[] args) throws IOException {
  boolean fileinput=false;
  Scanner scanner;
  PrintStream writer;
  if (fileinput) {
    scanner=new Scanner(System.in);
    System.out.println("String_Node_Str");
    String inputpath=scanner.nextLine();
    System.out.println("String_Node_Str");
    String outputpath=scanner.nextLine();
    scanner.close();
    scanner=new Scanner(new File(inputpath));
    writer=new PrintStream(new File(outputpath));
  }
 else {
    scanner=new Scanner(new File("String_Node_Str"));
    writer=new PrintStream(new File("String_Node_Str"));
  }
  String s=scanner.nextLine();
  StringTokenizer st=new StringTokenizer(s,"String_Node_Str");
  String type=st.nextToken().substring(8);
  StringTokenizer st2=new StringTokenizer(st.nextToken(),"String_Node_Str");
  StringTokenizer stdate=new StringTokenizer(st2.nextToken(),"String_Node_Str");
  String[] dateymd={stdate.nextToken(),stdate.nextToken(),stdate.nextToken()};
  String date_recorded=dateymd[1] + "String_Node_Str" + dateymd[2]+ "String_Node_Str"+ dateymd[0];
  String timestamp=st2.nextToken();
  String logname="String_Node_Str";
  String schema_version="String_Node_Str";
  String software_version="String_Node_Str";
  writer.println("String_Node_Str");
  writer.println("String_Node_Str" + logname + "String_Node_Str");
  writer.println("String_Node_Str" + schema_version + "String_Node_Str");
  writer.println("String_Node_Str" + date_recorded + "String_Node_Str");
  writer.println("String_Node_Str" + software_version + "String_Node_Str");
  writer.println("String_Node_Str");
  writeSensorData(scanner,writer,st,type,timestamp);
  while (scanner.hasNextLine()) {
    s=scanner.nextLine();
    st=new StringTokenizer(s,"String_Node_Str");
    type=st.nextToken().substring(8);
    st2=new StringTokenizer(st.nextToken(),"String_Node_Str");
    timestamp=st2.nextToken() + "String_Node_Str" + st2.nextToken();
    writeSensorData(scanner,writer,st,type,timestamp);
  }
  writer.println("String_Node_Str");
  writer.print("String_Node_Str");
  for (int x=0; x < sensor_type.size(); x++) {
    writer.print("String_Node_Str" + sensor_type.get(x) + "String_Node_Str"+ sensor_quant.get(x));
    if (x < sensor_type.size() - 1) {
      writer.print("String_Node_Str");
    }
  }
  writer.println("String_Node_Str");
  writer.print("String_Node_Str");
  System.out.println("String_Node_Str");
}

Fixed version (ground truth):
public static void main(String[] args) throws IOException {
  boolean fileinput=false;
  Scanner scanner;
  PrintStream writer;
  if (fileinput) {
    scanner=new Scanner(System.in);
    System.out.println("String_Node_Str");
    String inputpath=scanner.nextLine();
    System.out.println("String_Node_Str");
    String outputpath=scanner.nextLine();
    scanner.close();
    scanner=new Scanner(new File(inputpath));
    writer=new PrintStream(new File(outputpath));
  }
 else {
    scanner=new Scanner(new File("String_Node_Str"));
    writer=new PrintStream(new File("String_Node_Str"));
  }
  String s=scanner.nextLine();
  StringTokenizer st=new StringTokenizer(s,"String_Node_Str");
  String type=st.nextToken().substring(8);
  StringTokenizer st2=new StringTokenizer(st.nextToken(),"String_Node_Str");
  String date=st2.nextToken();
  StringTokenizer stdate=new StringTokenizer(date,"String_Node_Str");
  String[] dateymd={stdate.nextToken(),stdate.nextToken(),stdate.nextToken()};
  String date_recorded=dateymd[1] + "String_Node_Str" + dateymd[2]+ "String_Node_Str"+ dateymd[0];
  String timestamp=date + "String_Node_Str" + st2.nextToken();
  String logname="String_Node_Str";
  String schema_version="String_Node_Str";
  String software_version="String_Node_Str";
  writer.println("String_Node_Str");
  writer.println("String_Node_Str" + logname + "String_Node_Str");
  writer.println("String_Node_Str" + schema_version + "String_Node_Str");
  writer.println("String_Node_Str" + date_recorded + "String_Node_Str");
  writer.println("String_Node_Str" + software_version + "String_Node_Str");
  writer.println("String_Node_Str");
  writeSensorData(scanner,writer,st,type,timestamp);
  while (scanner.hasNextLine()) {
    s=scanner.nextLine();
    st=new StringTokenizer(s,"String_Node_Str");
    type=st.nextToken().substring(8);
    st2=new StringTokenizer(st.nextToken(),"String_Node_Str");
    timestamp=st2.nextToken() + "String_Node_Str" + st2.nextToken();
    writeSensorData(scanner,writer,st,type,timestamp);
  }
  writer.println("String_Node_Str");
  writer.print("String_Node_Str");
  for (int x=0; x < sensor_type.size(); x++) {
    writer.print("String_Node_Str" + sensor_type.get(x) + "String_Node_Str"+ sensor_quant.get(x));
    if (x < sensor_type.size() - 1) {
      writer.print("String_Node_Str");
    }
  }
  writer.println("String_Node_Str");
  writer.print("String_Node_Str");
  System.out.println("String_Node_Str");
}