#vulnerable code 
                                public static String readInFile(String fileName) {
        File file = new File(String.valueOf(peek()) + "/" + fileName);

        try {
            FileChannel fc = new FileInputStream(file).getChannel();

            push(file.getParent());

            ByteBuffer buf = allocateDirect(10);

            StringAppender appender = new StringAppender();
            int read;

            while (true) {
                buf.rewind();
                if ((read = fc.read(buf)) != -1) {
                    buf.rewind();
                    for (; read != 0; read--) {
                        appender.append((char) buf.get());
                    }
                }
                else {
                    break;
                }
            }

            pop();

            return appender.toString();

        }
        catch (FileNotFoundException e) {
            throw new TemplateError("cannot include template '" + fileName + "': file not found.");
        }
        catch (IOException e) {
            throw new TemplateError("unknown I/O exception while including '" + fileName + "' (stacktrace nested)", e);
        }
    } 
                            #location 27 
                            #vulnerability type RESOURCE_LEAK
#fixed code
                                public static String readInFile(String fileName) {
        File file = new File(String.valueOf(peek()) + "/" + fileName);

        try {
//            FileChannel fc = new FileInputStream(file).getChannel();

            FileInputStream instream = new FileInputStream(file);
            BufferedInputStream bufstream = new BufferedInputStream(instream);

            push(file.getParent());

            byte[] buf = new byte[10];
            int read;
            int i;

            StringAppender appender = new StringAppender();

            while ((read = bufstream.read(buf)) != -1) {
                for (i = 0; i < read; i++) {
                    appender.append((char) buf[i]);
                }
            }

            bufstream.close();
            instream.close();


//            ByteBuffer buf = allocateDirect(10);
//
//            StringAppender appender = new StringAppender();
//            int read;
//
//            while (true) {
//                buf.rewind();
//                if ((read = fc.read(buf)) != -1) {
//                    buf.rewind();
//                    for (; read != 0; read--) {
//                        appender.append((char) buf.get());
//                    }
//                }
//                else {
//                    break;
//                }
//            }

            pop();

            return appender.toString();

        }
        catch (FileNotFoundException e) {
            throw new TemplateError("cannot include template '" + fileName + "': file not found.");
        }
        catch (IOException e) {
            throw new TemplateError("unknown I/O exception while including '" + fileName + "' (stacktrace nested)", e);
        }
    }