Sorting multi-type string ArrayList in Java based on Integers

5377037 :

I have a data Set like this:

1,JOHN,1934
2,TERENCE,1914
3,JOHN,1964
4,JOHN,1904
5,JOHN,1924
6,JOHN,1954
7,JOHN,1944
8,JOHN,1984
9,JOHN,1974
10,JOHN,1994

Which I've loaded in ArrayList of String[] from Text file like this:

ArrayList<String[]> records = new ArrayList<>();
String fileLocation = System.getProperty("user.dir");
String dataPath = fileLocation + File.separator + "boys-names.txt";
try {
    try (BufferedReader br = new BufferedReader(new FileReader(dataPath))) {
        String line;
        while ((line = br.readLine()) != null) {
            String[] values = line.split(",");
            records.add(values);
        }
    }
} catch (IOException e) {
    e.printStackTrace();
}

I wanted to sort data set in increasing year like this:

4,JOHN,1904
2,TERENCE,1914
5,JOHN,1924
1,JOHN,1934
7,JOHN,1944
6,JOHN,1954
3,JOHN,1964
9,JOHN,1974
8,JOHN,1984
10,JOHN,1994

Problem: The built-in sorting method Collections.sort(list); of ArrayList only works on single type of data. But, in my case I have string with multi-type (string-integer) and sorting should base in Integers. So, is there any way to solve this problem?

Deadpool :

By using java-8 lambda expression, write custom Comparator that compares Integer values and use Integer.valueOf for converting String to Integer

List<String[]> list = new ArrayList<String[]>();

String[] ar1 = {"1","JOHN","1934"};
String[] ar2 = {"2","TERENCE","1914"};

list.add(ar1);
list.add(ar2);

list.sort((c1,c2)->Integer.valueOf(c1[2]).compareTo(Integer.valueOf(c2[2])));

list.forEach(i->System.out.println(Arrays.toString(i)));

Output

[2, TERENCE, 1914]
[1, JOHN, 1934]