Skip to main content

LinkedHashMap(Collection)

LinkedHashMap:-LinkedHashMap is child class of HashMap class where object store in the form of key value pair and maintain insertion order.
Example1:- TestMap.java
import java.util.*;
class TestMap
{
public static void main(String[]args)
{
Map m=new LinkedHashMap();
m.put(101,"Java");
m.put(102,"Cpp");
m.put(103,"C#");
m.put(104,"C");
m.put("Amit",101);
m.put("Neha",102);
System.out.println(m);
}
}
Output:-
{101=Java, 102=Cpp, 103=C#, 104=C, Amit=101, Neha=102}
Example2:-TestMap.java
import java.util.*;
class TestMap
{
public static void main(String[]args)
{
Map<Object,Object> m=new LinkedHashMap<Object,Object>();
m.put(101,"Java");
m.put(102,"Cpp");
m.put(103,"C#");
m.put(104,"C");
m.put("Amit",101);
m.put("Neha",102);
Set s=m.entrySet();
Iterator itr=s.iterator();
System.out.println("Key   :::::::::Value");
while(itr.hasNext())
{
Map.Entry me=(Map.Entry)itr.next();
System.out.println(me.getKey()+"    :::: "+me.getValue());
}
}
}
Output:-
Key   :::::::::Value
101    :::: Java
102    :::: Cpp
103    :::: C#
104    :::: C
Amit    :::: 101
Neha    :::: 102
Example3:- TestMap.java
import java.util.*;
class TestMap
{
public static void main(String[]args)
{
Map<Object,Object> m=new LinkedHashMap<Object,Object>();
m.put(101,"Java");
m.put(102,"java");
m.put(102,"C#");
m.put(104,null);
m.put("Amit",101);
m.put("Neha",102);
Set s=m.entrySet();
Iterator itr=s.iterator();
System.out.println("Key   :::::::::Value");
while(itr.hasNext())
{
Map.Entry me=(Map.Entry)itr.next();
System.out.println(me.getKey()+"    :::: "+me.getValue());
}
}
}
Output:-
Key   :::::::::Value
101    :::: Java
102    :::: C#
104    :::: null
Amit    :::: 101
Neha    :::: 102
Example4:- TestMap.java
import java.util.*;
class TestMap
{
public static void main(String[]args)
{
Map<Object,Object> m=new LinkedHashMap<Object,Object>();
m.put(101,null);
m.put(102,"java");
m.put(102,"C#");
m.put(104,null);
m.put(null,101);
m.put(null,102);
Set s=m.entrySet();
Iterator itr=s.iterator();
System.out.println("Key   :::::::::Value");
while(itr.hasNext())
{
Map.Entry me=(Map.Entry)itr.next();
System.out.println(me.getKey()+"    :::: "+me.getValue());
}
}
}
Output:-
Key   :::::::::Value
101    :::: null
102    :::: C#
104    :::: null
null    :::: 102
Example5:-TestMap.java
import java.util.*;
class Student
{
int rollno;
String name,course;
Student(int rollno,String name,String course)
{
this.rollno=rollno;
this.name=name;
this.course=course;
}
}
class TestMap
{
public static void main(String[]args)
{
Map<Object,Student> m=new LinkedHashMap<Object,Student>();
Student s1=new Student(101,"Neha","M.Tech");
Student s2=new Student(102,"Nisha","B.Tech");
Student s3=new Student(103,"Nehal","M.C.A");
Student s4=new Student(104,"Namita","MSC");
m.put(1011,s1);
m.put(1022,s2);
m.put(1033,s3);
m.put(1044,s4);
Set ss=m.entrySet();
Iterator itr=ss.iterator();
System.out.println("Key   :::::::::Value");
while(itr.hasNext())
{
Map.Entry me=(Map.Entry)itr.next();
Student s=(Student)me.getValue();
System.out.println(me.getKey()+"    :::: "+s.rollno+"  "+s.name+"  "+s.course);
}
}
}
Output:-
Key   :::::::::Value
1011    :::: 101  Neha  M.Tech
1022    :::: 102  Nisha  B.Tech
1033    :::: 103  Nehal  M.C.A

1044    :::: 104  Namita  MSC
Labels:

Comments

Post a Comment

Popular posts from this blog

Inner classes

Inner Classes:- class inside class or interface called inner class or nested class. Advantage of inner classes is grouping multiple classes and interfaces into a single class. Another big advantage of inner class is that inner class can happily access all the data or variables of outer class directly. Types of Nested classes:- There are two types of nested classes static and non-static nested classes. (A)Non –static inner classes:- 1)     Member inner class 2)     Anonymous inner class 3)     Local inner class (B)Static nested class Example1:-Outer.java class Outer { class Inner { void disp() { System.out.println("Hello This is Inner class Method"); } } public static void main(String[]args) { Inner in=new Inner(); in.disp(); } } Output:- C:\JAVATECH>javac Outer.java Outer.java:12: error: non-static variable this cannot be referenced from a static context Inner in=new Inner(); ...
Post a Comment
Read more

Inheritance-4

Example10:- class Student { Student() { System.out.println("This is super class Zero argument constructor"); } Student(String s) { System.out.println("This is super class One argument constructor"); } } class Test extends Student { Test() { super(null); System.out.println("This is sub class Zero argument constructor"); } public static void main(String[]args) { Test t=new Test(); } } Output:- C:\JAVATECH>javac Test.java C:\JAVATECH>java Test This is super class One argument constructor This is sub class Zero argument constructor Example11:- class Student { Student() { System.out.println("This is super class Zero argument constructor"); } Student(String s) { System.out.println("This is super class One argument constructor"); } } class Test extends Student { Test() { super(); super(null); System.out.println("This is su...
Post a Comment
Read more

Object,Data Hiding

Object:- Object is real time entity exist in the real world , the basic purpose of object is to transfer data from one location to another location.object is small memory , allocated inside primary memory(RAM).in java object created inside heap memory,actually in java RAM memory  is divided into some segment according to the type of variables for example. RAM==>Heap area+Stack area+String constant pool+class area  etc. when object created then inside object only non static class variables occupied memory and initialize with default values. non static class variables also known as instance variable reside into object in heap area,static variables occupied memory in class area at the time of class loading from HARD disk to RAM and all local variables occupied memory in stack area when reaching to variables. object  created from the class then what object contains is depend on class structure or class members.             ...
Post a Comment
Read more