Builder

class Student{
    private String name;
    private String phone;
    private String age;
    
    public static StudentBuilder getStudentBuilder(){ //to return StudentBuilder object 
        return new StudentBuilder();
    }
    
    public void print(){
        System.out.println(name+" "+phone+" "+age);
    }
    
    static class StudentBuilder{ //called without creating object
        private Student student = new Student(); //create student object
        public StudentBuilder setName(String name){ //set name and return builder object
            student.name = name;
            return this;
        }
        public StudentBuilder setPhone(String phone){ //set phone and return builder object
            student.phone = phone;
            return this;
        }
        public StudentBuilder setAge(String age){ //set age and return builder object
            student.age = age;
            return this;
        }
        public Student build(){ //return student object's clone.
            return student.clone(student);
        }
    }
    
    public Student clone(Student s){ //just copy one object to another
        Student student = new Student();
        student.name = s.name;
        student.phone = s.phone;
        student.age = s.age;
        return student;
    }
}

public class Client{
    public static void main(String[] args){
        Student.getStudentBuilder()
                    .setName("Rohan")
                    .setPhone("9899899876")
                    .setAge("24")
                    .build()
                    .print();
    }
}