@Builder public class Student { private String name; private int age; private String gender; private String address; private String phoneNumber; } @Builder public class Student { private String name; private int age; private String gender; @Builder.Default private String address = "Unknown"; @Builder.Default private String phoneNumber = "Unknown"; } Student student = Student.builder() .name("John") .age(20) .gender("Male") .address("123 Main St") .phoneNumber("1234567890") .build();