Inheritance & interface Concept 

package javaresearch;

public interface DisplayData {

           

             void display_student_info();

}

package javaresearch;

public class Student implements DisplayData {

            String name;

    int age;

    String programme;

   public Student()

   {

              

   }

            public Student(String name, int age, String programme) {

                        super();

                        this.name = name;

                        this.age = age;

                        this.programme = programme;

            }

            @Override

            public void display_student_info() {

                        System.out.println("Name="+name+" "+"Age="+age+" "+"Programme="+programme);

                       

            }

   

   

   

}

package javaresearch;

public class GraduateStudent extends Student  {

           

           

            String streams;

            float m_per;

            public GraduateStudent(String name, int age, String programme, String streams, float m_per) {

                        super(name, age, programme);

                        this.streams = streams;

                        this.m_per = m_per;

            }

            @Override

           

            public void display_student_info() {

                        super.display_student_info();

                        System.out.println("Streams="+streams+" "+"Percentage="+m_per);

                       

            }

           

           

}

package javaresearch;

public class ResearchStudent extends Student  {

 String specialization;

 float expyrs;

public ResearchStudent(String name, int age, String programme, String specialization,float expyrs) {

            super(name, age, programme);

            this.specialization = specialization;

            this.expyrs = expyrs;

}

 @Override

public void display_student_info() {

             super.display_student_info();

            System.out.println("Specialization="+specialization+" "+"Experiance="+expyrs+”yrs”);

           

}

 }

package javaresearch;

public class MainStrudent {

            public static void main(String[] args) {

                        Student s1=new Student();

                GraduateStudent gs1=new GraduateStudent("govind", 26, "cse","science", 74.9f);

                GraduateStudent gs2=new GraduateStudent("geeta", 22, "cse","science", 79.9f);

                ResearchStudent rs1=new ResearchStudent("sachin", 27, "Electrical","power system",2.6f);

                ResearchStudent rs2=new ResearchStudent("sonali", 29, "cse","software engineering", 5.5f);

                System.out.println("-----------Graduate Student Information------");

                gs1.display_student_info();

                gs2.display_student_info();

                System.out.println("-----------Research Student Information------");

                        rs1.display_student_info();

                rs2.display_student_info();

               

               

        

       

     }

}

o/p view:--------------

-----------Graduate Student Information------

Name=govind Age=26 Programme=cse

Streams=science Percentage=74.9

Name=geeta Age=22 Programme=cse

Streams=science Percentage=79.9

-----------Research Student Information------

Name=sachin Age=27 Programme=Electrical

Specialization=power system Experiance=2.6 yrs

Name=sonali Age=29 Programme=cse

Specialization=software engineering Experiance=5.5 yrs