How to compare the following file format?

Question

I have to compare the two files having 50K records in each file. The records are in text file but in following format :

Each line is having records.

1. If the records are same in both the files (comparing line by line) then we have to find the difference in corresponding records.
2. If the records are different (check at line 4) then increment the line in text file2 by one line and print this record of file2 as a new record not found in file1 and increment till it finds the record in file1 then compare the records in both lines.

Is this possible that we can compare the two files in this format.

EDIT

    private void compareFiles(File sourceFile, File targetFile, XlxsDataUtility resultFile)
        throws IOException {

    FixedFormatManager manager = new FixedFormatManagerImpl();

    FileInputStream fis = new FileInputStream(sourceFile);
    DataInputStream dis = new DataInputStream(fis);

    BufferedReader sourceReader = new BufferedReader(new InputStreamReader(dis));
    String sourceLine;

    FileInputStream fis2 = new FileInputStream(targetFile);
    DataInputStream dis2 = new DataInputStream(fis2);

    BufferedReader targetReader = new BufferedReader(new InputStreamReader(dis2));
    String targetLine;

    sourceReader.readLine();
    targetReader.readLine();

    StringBuilder stringBuilder = new StringBuilder();
    StringBuilder differetLines = new StringBuilder();
    int line = 1;
    while ((sourceLine = sourceReader.readLine()) != null && (targetLine = targetReader.readLine()) != null) {
        line++;

        // here i have used fixedformatManger ancientprogramming api to parse the text.
        Record1 record1 = manager.load(Record1.class, sourceLine);
        Record2 record2 = manager.load(Record2.class, targetLine);

        if (record1.getBlock().trim().equals(record2.getBlock().trim())
                && record1.getId().trim().equals(record2.getId().trim())) {

            int minimum = Math.min(sourceLine.length(), targetLine.length());
            int maximum = Math.max(sourceLine.length(), targetLine.length());

            int index = 0;

            String fromIndex = null;
            String toIndex = null;

            while (index < minimum) {

                char sourceChar = sourceLine.charAt(index);
                char targetChar = targetLine.charAt(index);

                if (sourceChar != targetChar) {
                    stringBuilder.append(stringBuilder.length() > 0 ? ", " : "").append(index + 1).append(" - ");
                    while ((index < minimum) && (sourceChar != targetChar))
                        index++;

                    if (index == minimum) {
                        stringBuilder.append(maximum);
                        index = maximum;
                    } else {
                        stringBuilder.append(index);
                    }
                    index++;
                    resultFile.addRowData(record2.getId().trim(), String.valueOf(sourceChar),
                            String.valueOf(targetChar), stringBuilder.toString(), record1.getBlock(),
                            String.valueOf(line));
                }
                index++;
                // resultFile.addRowData(stringBuilder.toString());
                stringBuilder.delete(0, stringBuilder.length());
            }

            if (minimum != maximum && index < maximum) {
                stringBuilder.append(stringBuilder.length() > 0 ? ", " : "").append(minimum + 1).append(" - ")
                        .append(maximum);
                resultFile.addRowData(record1.getId().trim(), record2.getId().trim(), stringBuilder.toString(),
                        record1.getBlock(), String.valueOf(line));
                stringBuilder.delete(0, stringBuilder.length());
            }

            // System.out.println(stringBuilder.toString());
        } else {
            // records in both lines are different
            targetReader.readLine(); // I am not sure it works here or not
            differetLines.append(record1.getBlock() + record1.getId().trim() + " is not found in "
                    + record2.getBlock() + record2.getId().trim() + " at line Number :: " + line + "\n");
        }
    }

    sourceReader.close();
    targetReader.close();

    writeDifferenceTofile(differetLines.toString(),"Flat_File New_Records");

}

}