import java.util.*;

public class Main {
    record Point(int x, int y) {}

    public static void main(String[] args) {
        Point p = new Point(3, 4);
        System.out.println(p);                     // generated toString
        System.out.println(p.x() + p.y());         // accessors: x(), not getX()
        System.out.println(p.equals(new Point(3, 4)));
        System.out.println(new HashSet<>(List.of(p)).contains(new Point(3, 4)));
    }
}

Point[x=3, y=4]
7
true
true

public class Main {
    record Range(int lo, int hi) {
        Range {                                    // compact canonical constructor: no parameter list
            if (lo > hi) throw new IllegalArgumentException("lo > hi: " + lo + " > " + hi);
        }
        int length() { return hi - lo; }           // extra methods are fine
        static Range of(int a, int b) {            // static factory
            return new Range(Math.min(a, b), Math.max(a, b));
        }
    }

    record Email(String value) {
        Email {
            value = value.trim().toLowerCase();     // reassign the parameter, not this.value
        }
    }

    public static void main(String[] args) {
        System.out.println(new Range(2, 9).length());
        System.out.println(Range.of(9, 2));
        System.out.println(new Email("  Asha@Mail.COM "));
        try {
            new Range(5, 1);
        } catch (IllegalArgumentException e) {
            System.out.println("rejected: " + e.getMessage());
        }
    }
}

7
Range[lo=2, hi=9]
Email[value=asha@mail.com]
rejected: lo > hi: 5 > 1

import java.util.*;

public class Main {
    record Team(String name, List<String> members) {
        Team {
            members = List.copyOf(members);        // defensive, unmodifiable copy
        }
    }

    public static void main(String[] args) {
        List<String> list = new ArrayList<>(List.of("Asha"));
        Team t = new Team("core", list);
        list.add("Ravi");                          // doesn't leak into the record
        System.out.println(t.members());
        try {
            t.members().add("Mei");
        } catch (UnsupportedOperationException e) {
            System.out.println("members are read-only");
        }
    }
}

[Asha]
members are read-only