Practical 1.1

/* Understand the Generic class

* Write a Java Program to demonstrate a Generic Class

* Author: Vikram

* rollno:

* div:

* */ Solution

public class GenericClassExample <T>{

private T dvariable;

public T getDvariable() {

return dvariable;

}

public void setDvariable(T dvariable) {

this.dvariable = dvariable;

}

public static void main(String []args)

{

GenericClassExample<Integer> intvar=new GenericClassExample<>(); intvar.setDvariable(10);

System.out.println(“Variable value=“+intvar.getDvariable());

GenericClassExample<String> strvar=new GenericClassExample<>(); strvar.setDvariable(“Sukhiram”);

System.out.println(“Variable value=“+strvar.getDvariable());

}

}

Output

Variable value = 10

Variable value = Sukhiram

Practical 1.2

/*

* Practical b1

* Write a program in java that will use Generic methods

* There are following kind of Generic Types

* T Type

* E Element

* k Key

* v Value

* N Number

*/

public class GenericMethod1 {

//print array is generic method

public static <E> void printArray(E[] inputArray)

{

//display array element

for(E element:inputArray)

{

System.out.printf(“%s,”,element);

}

System.out.println();

}

public static void main(String[] args) {

// TODO Auto-generated method stub Integer [] intArray= {1,2,3,4,5,6};

Double [] doubleArray= {1.45,2.35,4.63,8.56}; Character [] charArray= {‘H’,’E’,’L’,’L’,’0’}; printArray(intArray);

printArray(doubleArray); printArray(charArray);

}

}

Output

1, 2, 3, 4, 5, 6,

1.45, 2.35, 4.63, 8.56,

H, E, L, L, O,

Practical 1.2a

/*

* Write a program in java that will use Generic methods

* There are following kind of Generic Types

* T Type

* E Element

* k Key

* v Value

* N Number

* understand the use of k,v types

* S,V

*/

class Pair<K,V>

{

private K key; private V value;

public Pair(K key, V value)

{

this.key = key;

this.value = value;

}

public K getKey()

{return key;}

public void setKey(K key)

{this.key = key;}

public V getValue()

{return value;}

public void setValue(V value)

{this.value = value;}

}

public class GenericMethod2 {

public static <K,V> boolean compare(Pair<K,V>p1,Pair<K,V>p2) {return p1.getKey().equals(p2.getKey()) &&

p1.getValue().equals(p2.getValue());

};

public static void main(String[] args) {

// TODO Auto-generated method stub Pair<Integer,String>p1=new Pair<>(1,”aaa”); Pair<Integer,String>p2=new Pair<>(2,”bbb”); boolean result=GenericMethod2.compare(p1, p2); System.out.println(result);

}

}

Output

false

Practical 1.3

Write a program to demonstrate unbound Wildcard in List Interface

import java.util.ArrayList; import java.util.Iterator; import java.util.List;

/*

* Write a program in java to understand the use

* of unbound wildcards ?

*/

public class unboundWildcardExample {

public static void printArray(List<?> mylist)

{

Iterator itr=mylist.iterator(); while(itr.hasNext())

{

System.out.println(itr.next());

}

System.out.println(“ “);

}

public static void main(String[] args) {

// TODO Auto-generated method stub

ArrayList <Integer>mynumberlist=new ArrayList<Integer>(); mynumberlist.add(1);

mynumberlist.add(2); mynumberlist.add(3); printArray(mynumberlist);

ArrayList <String>mynamelist=new ArrayList<String>(); mynamelist.add(“Suresh”);

mynamelist.add(“Ramesh”); mynamelist.add(“Jayesh”); mynamelist.add(“Mahesh”); printArray(mynamelist);

}

}

Output

1

2

3

––––––––

Suresh

Ramesh

Jayesh

Mahesh

––––––––

Practical 1.3a

Write a program to demonstrate upper Wildcard in List Interface

import java.util.ArrayList; import java.util.Iterator; import java.util.List;

/*

* Write a program in java to understand the use

* of upperbound wildcards ? extends

*/

public class upperboundWildcardExample {

public static void sumofElements(List<? extends Number> numberlist)

{

double sum=0.0;

for (Number n : numberlist) sum += n.doubleValue(); System.out.println(“Sum of all elements is=“+sum);

}

public static void main(String []args) {

ArrayList <Integer>intlist=new ArrayList<Integer>(); intlist.add(1);

intlist.add(2); intlist.add(3); sumofElements(intlist);

ArrayList <Double>dblist=new ArrayList<Double>(); dblist.add(24.56);

dblist.add(21.24); dblist.add(124.16); dblist.add(121.14); sumofElements(dblist);

}

}

Output

Sum of all elements is=6.0

Sum of all elements is=291.09999999999997