Program: 12851
Project: 12851
Buggy source:
static Line fromString(String lineString){
  Line l=new Line();
  boolean inString=false;
  boolean hasLineNumber=false;
  boolean isComment=false;
  Command currentCommand=new Command();
  l.commands.add(currentCommand);
  l.length=4;
  lineString=lineString.trim();
  String upperLineString=lineString.toUpperCase();
  for (int i=0; i < lineString.length(); i++) {
    if (!hasLineNumber) {
      int lineNumber=0;
      for (; i < lineString.length() && isDigit(lineString.charAt(i)); i++) {
        lineNumber=lineNumber * 10 + lineString.charAt(i) - '0';
      }
      i--;
      l.setNumber(lineNumber);
      hasLineNumber=true;
    }
 else     if (inString || isComment) {
      if (!isComment && lineString.charAt(i) == '"') {
        inString=false;
      }
      currentCommand.parts.add(new Command.ByteOrToken((byte)lineString.charAt(i)));
      l.length++;
    }
 else     if (lineString.charAt(i) == '"') {
      inString=true;
      currentCommand.parts.add(new Command.ByteOrToken((byte)lineString.charAt(i)));
      l.length++;
    }
 else     if (lineString.charAt(i) == STATEMENT_BREAK) {
      currentCommand=new Command();
      l.commands.add(currentCommand);
      l.length++;
    }
 else     if (lineString.charAt(i) == '?') {
      Command.ByteOrToken part=new Command.ByteOrToken(TOKEN.PRINT);
      currentCommand.parts.add(part);
      l.length++;
    }
 else {
      TOKEN match=Command.TOKEN.findMatch(upperLineString,i);
      if (match != null) {
        if (match == TOKEN.REM) {
          isComment=true;
        }
        Command.ByteOrToken part=new Command.ByteOrToken(match);
        currentCommand.parts.add(part);
        for (int j=0; j + i <= match.toString().length(); j++) {
          while (lineString.charAt(i + j) == ' ') {
            i++;
          }
        }
        i+=match.toString().length() - 1;
        if (isComment) {
          while (i + 1 < lineString.length() && lineString.charAt(i + 1) == ' ') {
            i++;
          }
        }
        l.length++;
      }
 else {
        if (lineString.charAt(i) != ' ') {
          currentCommand.parts.add(new Command.ByteOrToken((byte)upperLineString.charAt(i)));
          l.length++;
        }
      }
    }
  }
  return l;
}

Fixed version (ground truth):
static Line fromString(String lineString){
  Line l=new Line();
  boolean inString=false;
  boolean hasLineNumber=false;
  boolean isComment=false;
  Command currentCommand=new Command();
  l.commands.add(currentCommand);
  l.length=4;
  String upperLineString=lineString.toUpperCase();
  for (int i=0; i < lineString.length(); i++) {
    if (!hasLineNumber) {
      int lineNumber=0;
      for (; i < lineString.length() && isDigit(lineString.charAt(i)); i++) {
        lineNumber=lineNumber * 10 + lineString.charAt(i) - '0';
      }
      i--;
      l.setNumber(lineNumber);
      hasLineNumber=true;
    }
 else     if (inString || isComment) {
      if (!isComment && lineString.charAt(i) == '"') {
        inString=false;
      }
      currentCommand.parts.add(new Command.ByteOrToken((byte)lineString.charAt(i)));
      l.length++;
    }
 else     if (lineString.charAt(i) == '"') {
      inString=true;
      currentCommand.parts.add(new Command.ByteOrToken((byte)lineString.charAt(i)));
      l.length++;
    }
 else     if (lineString.charAt(i) == STATEMENT_BREAK) {
      currentCommand=new Command();
      l.commands.add(currentCommand);
      l.length++;
    }
 else     if (lineString.charAt(i) == '?') {
      Command.ByteOrToken part=new Command.ByteOrToken(TOKEN.PRINT);
      currentCommand.parts.add(part);
      l.length++;
    }
 else     if (lineString.charAt(i) == ' ') {
      continue;
    }
 else {
      TOKEN match=Command.TOKEN.findMatch(upperLineString,i);
      if (match != null) {
        Command.ByteOrToken part=new Command.ByteOrToken(match);
        currentCommand.parts.add(part);
        if (match == TOKEN.REM || match == TOKEN.DATA) {
          isComment=true;
        }
        for (int j=0; j < match.toString().length(); j++, i++) {
          while (i < lineString.length() && lineString.charAt(i) == ' ') {
            i++;
          }
        }
        if (!isComment) {
          i--;
        }
        l.length++;
      }
 else {
        if (lineString.charAt(i) != ' ') {
          currentCommand.parts.add(new Command.ByteOrToken((byte)upperLineString.charAt(i)));
          l.length++;
        }
      }
    }
  }
  return l;
}