Type mismatch: cannot convert from ArrayList<?> to Collection<BlockPair>

HashMap hints= new HashMap();

hints.put(EncodeHintType.CHARACTER_SET, "utf-8");

hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);

hints.put(EncodeHintType.MARGIN,2);

try {

BitMatrix bitMatrix =new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height);

Path file=new File("D:/MyEclipse/code/img.png").toPath();

MatrixToImageWriter.writeToPath(bitMatrix, format, file);

} catch (Exception e) {

e.printStackTrace();

}

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 

Type mismatch: cannot convert from ArrayList<?> to Collection<BlockPair>

Cannot instantiate the type ArrayList<?>

Syntax error on token "<", ? expected after this token