Spark cannot connect to Openfire Server

If you try login or new register using spark to openfire and openfire runing but you are enable to connect openfire .
  
   you can connect to openfire by other system using spark then change advanced setting of spark
  

   Go to advanced tab of spark and check use old SSL port method

how to install spark on ubuntu

Step 1:

  download spark  click here
 
   or

 use this command

wget http://download.igniterealtime.org/spark/spark_2_6_3.tar.gz

 

step 2: 

  Now  extract tar file Using this command

 tar -zxvf spark_2_7_0.tar.gz

and it makes Spark folder

Step 3:

  

  Now  go to in Spark  folder and run this Command

Dell-System-Inspiron-N4110:~/Spark$  ./Spark

After this you can see spark windows

How to check HashSet Empty Or not

import java.util.HashSet;
import java.util.Set;

public class IsEmpty {
   
public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        //print hashset
        System.out.println("hashset = "+hs);
       
        System.out.println(hs.isEmpty());
       
        HashSet<String> hs2 = new HashSet<String>();
       
        System.out.println(hs2.isEmpty());
    }

}






 Output:


 hashset = [javascript, php, html, java, mysql]

false

true

How to count number of element in HashSet

 Size() Method return number of element in the HashSet.

import java.util.HashSet;
import java.util.Set;

public class CountElement {
   
    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        //print hashset
        System.out.println("hashset = "+hs);
       
       
        /*
         * Returns the number of elements in set. If this set contains more than
         * Integer.MAX_VALUE elements, returns  Integer.MAX_VALUE.
         */
       
        System.out.println("Size of hashset = "+hs.size());
    }

}





Output:


hashset = [javascript, php, html, java, mysql]

Size of hashset = 5

How to find does HashSet contains elements or not

Returns true if this set contains the specified element.we can say returns true if and only if this set contains an element e such that (o==null ? e==null :
 o.equals(e)).

import java.util.HashSet;
import java.util.Set;

public class ContailsElement {
   
    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        //print hashset
        System.out.println("hashset = "+hs);
       
        System.out.println(hs.contains("java"));
        System.out.println(hs.contains("HTml"));
        System.out.println(hs.contains("delhi"));
       
    }

}


hashset = [javascript, php, html, java, mysql]

true

false

false

How To Convert Hashset To Array

import java.util.HashSet;
import java.util.Set;

public class HashSetToArray {
   
    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        //print hashset
        System.out.println("hashset = "+hs);
       
        String [] arr = new String[hs.size()];
       
        /*
         * Returns an array containing all of the
         * elements in hs set
         */
        hs.toArray(arr);
       
        System.out.println("Array is ");
       
        for (String str : arr) {
            System.out.println("Element is = "+str);
        }
       
    }

}

Output:

hashset = [javascript, php, html, java, mysql]

Array is

Element is = javascript

Element is = php

Element is = html

Element is = java

Element is = mysql

How to Remove Set From HashSet

package com.javapro.hashset;

import java.util.HashSet;
import java.util.Set;

public class RemoveAll {

    public static void main(String[] args) {

        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        // print hashset
        System.out.println("Before Remove Element hs = " + hs);

        HashSet<String> hs2 = new HashSet<String>();
        hs2.add("java");
        hs2.add("html");
        hs2.add("two");

        System.out.println("hs2 is = " + hs2);

        /*
         * Removes from hs set all of its elements that are contained in the hs2
         * collection
         */

        hs.removeAll(hs2);

        System.out.println("After Remove All hs = " + hs);

    }

}

Output:

Before Remove Element hs = [javascript, php, html, java, mysql]


hs2 is = [two, html, java]

After Remove All hs = [javascript, php, mysql]

How to remove all element from HashSet

import java.util.HashSet;
import java.util.Set;

public class RemoveAll {
   
public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");
       
        //print hashset
        System.out.println("Before Remove element hashset is = "+hs);
       
         /*
          * Removes all of the elements from  set
          */
        hs.clear();
       
        System.out.println("After Remove elements hashset is ="+hs);
       
    }

}






Output:


Before Remove element hashset is = [javascript, php, html, java, mysql]

After Remove elements hashset is =[]

How To Remove Element of Hashset

import java.util.HashSet;
import java.util.Set;

public class RemoveElement {
   
    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");
       
        //print hashset
        System.out.println("Before Remove element hashset is = "+hs);
       
        /*
         * Removes the specified element from  set
         * if it is present
         */
        hs.remove("php");
       
        System.out.println("After Remove element hashset is ="+hs);
       
    }

}




Output:


Before Remove element hashset is = [javascript, php, html, java, mysql]

After Remove element hashset is =[javascript, html, java, mysql]

How to copy all element of a Hashset to other

import java.util.HashSet;
import java.util.Set;

public class AddAll {

    public static void main(String[] args) {

        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");

        // print hashset
        System.out.println("hs is = " + hs);
       
        HashSet<String> hashSet = new HashSet<String>();
       
        /*
         * Adds all of the elements in the specified
         *  collection to hashset collection
         */
       
        hashSet.addAll(hs);
       
        System.out.println("hashset is="+hashSet);

    }

}





Output:


hs is = [javascript, php, html, java, mysql]

hashset is=[javascript, php, java, html, mysql]

How to convert array to HashSet

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class ArrayToHashSet {
    public static void main(String[] args) {

        String[] arr = { "one", "two", "third" };
       

        Set<String> hs = new HashSet<String>(Arrays.asList(arr));

        // print hashset

        System.out.println("hashset is =" + hs);

    }
}

Output:

hashset is =[two, one, third]

How to Convert a HashSet to an ArrayList

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class HashSetToList {


    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("mysql");
       
        //print hashset
        System.out.println("hashset = "+hs);
       
      List<String> list = new ArrayList<String>(hs);
       
      System.out.println("list from hashset = "+list);
     
    }
   
}

Output:

hashset = [javascript, php, html, java, mysql]


list from hashset = [javascript, php, html, java, mysql]

How to storing Java Object In HashSet

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class HashSetOfObject {
    public static void main(String[] args) {
       
        Set<User> hs = new HashSet<User>();

        hs.add(new User("shivam",1213));
        hs.add(new User("yogesh",8383));
        hs.add(new User("ashwani", 8287));
       
        Iterator<User> itr =hs.iterator();
        while (itr.hasNext()) {
            User user = (User) itr.next();
            System.out.println("userName ="+user.getName()+" userId = "+user.getUserId());
        }
       
       
    }
}

class User{
       
    private String name;
    private int userId;
   
    public User(String name, int userId) {
        super();
        this.name = name;
        this.userId = userId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }
    
}



Output:

userName =ashwani userId = 8287

userName =shivam userId = 1213

userName =yogesh userId = 8383

How to create Hashset In Java

import java.util.HashSet;
import java.util.Set;

public class CreateHashset {
   
    public static void main(String[] args) {
       
        Set<String> hs = new HashSet<String>();
       
   
        hs.add("java");
        hs.add("php");
        hs.add("html");
        hs.add("javascript");
        hs.add("vb");
       
        //print hashset
        System.out.println("hashset = "+hs);
       
    }
}

Output:

hashset = [javascript, php, html, java, vb]

Java HashSet Examples

How to create Hashset In Java

How to storing Java Object In HashSet 

How to Convert a HashSet to an ArrayList 

How to convert array to HashSet

How to copy all element of a Hashset to other

How To Remove Element of Hashset

How to remove all element from HashSet

How to Remove Set From HashSet

How To Convert Hashset To Array

  

How to find does HashSet contains elements or not 

How to count number of element in HashSet

How to check HashSet Empty Or not

How to Convert Array to Vector

import java.util.Arrays;
import java.util.Vector;

public class ArrayToVector {

    public static void main(String[] args) {
      

        String [] arr ={"java","c","cpp","php","html"};
       
        Vector<String> vector = new Vector<String>(Arrays.asList(arr));

        for (String str : vector) {

            System.out.println("Element is = "+str);

        }

    }

}

 Output:

Element is = java

Element is = c

Element is = cpp

Element is = php

Element is = html

How to use retailAll in vector

Retains only the elements in vector that are contained in the specified collection. In other words, removes from vector all of its elements that are not contained in the specified collection.


import java.util.ArrayList;
import java.util.List;
import java.util.Vector;

public class RetainAll {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
           
        List<String> list = new ArrayList<String>();
      
        list.add("hockey");
        list.add("php");
        list.add("java");
      
        /*
         * Retains only the elements in this
         *  Vector that are contained in the
         *   specified Collection.
         */
        vector.retainAll(list);
      
        System.out.println("After retainAll vector is = "+vector);
      
    }
   
   
}

Output:

Vector = [cricket, hockey, football, tennish]

After retainAll vector is = [hockey]
 

How to insert element in vector

import java.util.Vector;

public class AddElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);

        /*
         * Inserts the specified element at the specified
         * position in this Vector.
         */
        vector.add(1, "java");
               
        System.out.println("vector after insert element = "+vector);
    }
}

Output:

Vector = [cricket, hockey, football, tennish]

vector after insert element = [cricket, java, hockey, football, tennish]

How to replace element of vector

 We can replace any specific index element by other element using set(int index,element) method.


import java.util.Vector;

public class ReplaceElement {
   
 public static void main(String[] args) {
       
         Vector<String> vector = new Vector<String>();
         //add element in vector
         vector.add("cricket");
         vector.add("hockey");
         vector.add("football");
         vector.add("tennish");
       
         // print vector
         System.out.println("Before replace Vector is = "+vector);
       
         /*
          * Replaces the element at the specified
          * position in this Vector with the
          *  specified element.
          */
         vector.set(1,"Apple");
       
         System.out.println("After Replace element vector is = "+vector);
               
    }

}


Output:

Before replace Vector is = [cricket, hockey, football, tennish]

After Replace element vector is = [cricket, Apple, football, tennish]
 

How to count number of element in vector

Size() Method return number of element in the vector.

import java.util.Vector;

public class CountElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector is = "+vector);
      
            /*
             * Returns the number of components in this vector.
             */
        System.out.println("size = "+vector.size());
    }

}

Output:

Vector is = [cricket, hockey, football, tennish]

size = 4
 

How to shuffle elements in Vector

import java.util.Collections;
import java.util.Vector;

public class Shuffle {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
               
        /*
         * Randomly permutes the specified list using a
         *  default source of randomness.
         */
        Collections.shuffle(vector);
      
        System.out.println("Vector after first Shuffle = "+vector);
      
        Collections.shuffle(vector);
      
        System.out.println("Vector after second Shuffle = "+vector);
      
    }
}
   
Output:
Vector = [cricket, hockey, football, tennish]

Vector after first Shuffle = [tennish, cricket, football, hockey]

Vector after second Shuffle = [cricket, hockey, tennish, football]

How to find does Vector contains elements or not

we use contains() and  Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that (o==null ?  e==null : o.equals(e)).


import java.util.Vector;

public class ContailsElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
      
        System.out.println(vector.contains("cricket"));
      
        System.out.println(vector.contains("apple"));
               
  }

}

Output:

 Vector = [cricket, hockey, football, tennish]

true

false

How to get element of vector

import java.util.Vector;

public class GetElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
      
        /*
         * Returns the element at the specified
         * position in this Vector.
         */
        System.out.println("element at index 2 is = "+vector.get(2));
               
            }

}



Output:

Vector = [cricket, hockey, football, tennish]

element at index 2 is = football
 

How to get sub list from Vector

we can use sublist(fromindex,toindex) for get sublist from a vector.

import java.util.List;
import java.util.Vector;

public class GetSubList {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
        vector.add("java");
      
        // print vector
        System.out.println("Vector = "+vector);
               
        /*
         * Returns a view of the portion of this
         *  List between fromIndex, inclusive, and
         *  toIndex, exclusive. (If  fromIndex and toIndex are equal,
         *  the returned List is empty.) T
         */
      
     List<String> list = vector.subList(1,3);
    
     System.out.println("list is ="+list);
      
    }

}

Output:

Vector = [cricket, hockey, football, tennish, java]

list is =[hockey, football]

How to Remove List From Vector

import java.util.ArrayList;
import java.util.List;
import java.util.Vector;

public class RemoveList {
   
      public static void main(String[] args) {
           
             Vector<String> vector = new Vector<String>();
             //add element in vector
             vector.add("cricket");
             vector.add("hockey");
             vector.add("football");
             vector.add("tennish");
           
             // print vector
             System.out.println("Vector = "+vector);
           
             List<String> list = new ArrayList<String>();
             list.add("hockey");
             list.add("tennish");
             list.add("apple");
             list.add("java");
           
             System.out.println("list is = "+list);
           
             /*
              * Removes from this Vector all of its
              *  elements that are contained in the
              *  specified Collection.
              */
             vector.removeAll(list);
           
             System.out.println("Vector after remove list = "+vector);
                   
                }

}


Output:
Vector = [cricket, hockey, football, tennish]

list is = [hockey, tennish, apple, java]

Vector after remove list = [cricket, football]

How To Remove Element of Vector

import java.util.Vector;

public class RemoveElement {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
      
      
        /*
         * Removes the element at the specified position
         * in this Vector. Shifts any subsequent elements
         * to the left (subtracts one from their indices).
         * Returns the element that was removed from the
         *  Vector.
         */
        vector.remove(1);
      
        System.out.println("After remove element vector is = "+vector);
               
            }
     
}

Output:

Vector = [cricket, hockey, football, tennish]

After remove element vector is = [cricket, football, tennish]

How to remove all element from vector

We can remove all element of vector using clear() method . clear() removes all element from the list and return empty list.


import java.util.Vector;

public class RemoveAll {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector is = "+vector);
      
        /*
         * Removes all of the elements from this
         * Vector. The Vector will be empty after
         *  this call returns (unless it throws an
         *   exception).
         */
        vector.clear();
      
        System.out.println("Vector After Clear is = "+vector);
               
    }

}


Output:

Vector is = [cricket, hockey, football, tennish]

Vector After Clear is = []

How to swap elements of vector

import java.util.Collections;
import java.util.Vector;

public class SwapElement {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Before swap Vector = "+vector);
      
        /*
         * Swaps the elements at the specified positions
         * in the specified list. (If the specified
         * positions are equal, invoking this method
         * leaves the list unchanged.)
         */
      
        Collections.swap(vector, 1, 3);
      
        System.out.println("After swap vector = "+vector);
               
            }   
   
}

Output:

Before swap Vector = [cricket, hockey, football, tennish]

After swap vector = [cricket, tennish, football, hockey]

How to add all elements of a list to Vector

import java.util.ArrayList;
import java.util.List;
import java.util.Vector;

public class AddAllElement {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
      
        List<String> list =  new ArrayList<>();
        list.add("java");
        list.add("c++");
        list.add("php");
      
        System.out.println("list = "+list);
      
        /*
         * Appends all of the elements in the specified
         * Collection to the end of this Vector, in the
         * order that they are returned by the specified
         *  Collection's Iterator.
         */

        vector.addAll(list);
      
       System.out.println("vector after add list ="+vector);
      
    }

}

Output:

Vector = [cricket, hockey, football, tennish]

list = [java, c++, php]

vector after add list =[cricket, hockey, football, tennish, java, c++, php]

Reverse order of all elements of Vector

import java.util.Collections;
import java.util.Vector;

public class ReverseAllelement {

    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Before reverse Vector = "+vector);
      
        /*
         * Reverses the order of the elements in the
         * specified list. This method runs in linear time.
         */
        Collections.reverse(vector);
      
      System.out.println("After reverse Vector = "+vector);
               
    }
}


Output:

Before reverse Vector = [cricket, hockey, football, tennish]

After reverse Vector = [tennish, football, hockey, cricket]

How To Shallow Copy Or Clone a Vector

import java.util.Vector;

public class CloneOfVector {
   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        // print vector
        System.out.println("Vector = "+vector);
   
        /*
         * Returns a clone of this vector. The copy will
         * contain a reference to a clone of the internal
         *  data array, not a reference to the original internal
         *  data array of this Vector object.
         */
      
        Vector<String> myvector = (Vector<String>) vector.clone();
      
        for (String str : myvector) {

        System.out.println("element is = "+str);
   
         }
      
    }

}

How To Copy Vector To Array

import java.util.Vector;

public class VectorToArray {
  
    public static void main(String[] args) {
       
        Vector<String> vector = new Vector<String>();
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
       
        // print vector
        System.out.println("Vector = "+vector);
       
        String [] arr = new String[vector.size()];
       
        //Returns an array containing all of the
        //elements in this Vector in the correct order.
       
        vector.toArray(arr);

        System.out.println("Array is :");

        for (int i = 0; i < arr.length; i++) {
    System.out.println("Element is = "+arr[i]);
      
    }
              
   }

}




Output:

Vector = [cricket, hockey, football, tennish]

Array is :

Element is = cricket

Element is = hockey

Element is = football

Element is = tennish

Vector Iterator Example

import java.util.Iterator;
import java.util.Vector;

public class IterateVector {

   
    public static void main(String[] args) {
      
        Vector<String> vector = new Vector<String>();
      
        //add element in vector
        vector.add("cricket");
        vector.add("hockey");
        vector.add("football");
        vector.add("tennish");
      
        //Returns an iterator over the elements in
        //this list in proper sequence.
        Iterator<String> itr = vector.iterator();
        while (itr.hasNext()) {
            System.out.println("element is = "+itr.next());
           
        }
      
    }
   
}


Output:

element is = cricket

element is = hockey

element is = football

element is = tennish

How to storing Java Object In Vector

import java.util.Vector;

public class VectorOfObject {

    public static void main(String[] args) {

        Vector<User> vector = new Vector<User>();
        vector.add(new User("shivam",100));
        vector.add(new User("raja",200));
        vector.add(new User("mukesh",300));
        vector.add(new User("piyush",500));
       
        // print vector
        for (User user : vector) {
            System.out.println("user name="+user.getName()+" User id="+user.getUserId());
        }
   
    }
   
   
}

class User{

    private String name;
    private int userId;
   
    public User(String name, int userId) {
        super();
        this.name = name;
        this.userId = userId;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }
   
}


Output:

user name=shivam User id=100

user name=raja User id=200

user name=mukesh User id=300

user name=piyush User id=500

How to create Vector In java

import java.util.Vector;

public class CreateVector {
   
     public static void main(String[] args) {
       
         Vector<String> vector = new Vector<String>();
       
         //add element in vector
         vector.add("cricket");
         vector.add("hockey");
         vector.add("football");
         vector.add("tennish");
       
         // print vector
         System.out.println("Vector = "+vector);
               
            }
}


Output:

Vector = [cricket, hockey, football, tennish]

Java Vector Examples

How to create Vector In java 

How to storing Java Object In Vector

Vector Iterator Example

How To Copy Vector To Array 

How to Convert Array to Vector

How To Shallow Copy Or Clone a Vector

Reverse order of all elements of Vector 

How to add all elements of a list to Vector

How to swap elements of vector 

How to remove all element from vector 

How To Remove Element of Vector

How to Remove List From Vector 

How to get sub list from Vector

 How to get element of vector

How to find does Vector contains elements or not 

How to shuffle elements in Vector 

How to count number of element in vector 

How to replace element of vector

How to insert element in vector

How to use retailAll in vector

 

 

Container request filter in Jersey

Request filter is executed before the resource method is run and before the response is created. The filter has possibility to manipulate the request parameters including request headers or entity.

UserHandler.java 

package com.javaproficiency.jerseydemo.demo;

import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;

@Path("/user")
public class UserHander {
    @POST
    public Response addUser(@HeaderParam("token") String token) {
        System.out.println("token=" + token);
        return Response.status(Status.OK).entity(token).build();
    }

}

RequestFilter.java

package com.javaproficiency.jerseydemo.filter;

import java.io.IOException;

import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.ext.Provider;


@Provider
public class RequestFilter implements ContainerRequestFilter{

    public void filter(ContainerRequestContext requestContext) throws IOException {
               
        System.out.println("Filter token="+requestContext.getHeaderString("token"));
       
    }

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>JerseyDemo</display-name>
    <servlet>
        <servlet-name>RestServices</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>

        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>com.javaproficiency.jerseydemo.demo;com.javaproficiency.jerseydemo.filter</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>RestServices</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>
</web-app>

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>InstagramPost</groupId>
    <artifactId>InstagramPost</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <groupId>com.craterzone.instagrampost</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

<dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-server</artifactId>
            <version>2.13</version>
        </dependency>
           
        <dependency>       
            <groupId>org.glassfish.jersey.containers</groupId>
            <!-- if your container implements Servlet API older than 3.0, use "jersey-container-servlet-core" -->
            <artifactId>jersey-container-servlet</artifactId>
            <version>2.13</version>
        </dependency>

        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>javax.ws.rs-api</artifactId>
            <version>2.0</version>
        </dependency>


        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet</artifactId>
            <scope>provided</scope>
            <version>2.16</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
   
           <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-json-jackson</artifactId>
            <version>2.10.1</version>
        </dependency>
       
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.2</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.9.2</version>
        </dependency>

        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-grizzly2-http</artifactId>
            <version>2.16</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-grizzly2-servlet</artifactId>
            <version>2.16</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-jdk-http</artifactId>
            <version>2.16</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-simple-http</artifactId>
            <version>2.16</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-jetty-http</artifactId>
            <version>2.16</version>
        </dependency>
      <dependency>
    <groupId>org.glassfish.jersey.core</groupId>
    <artifactId>jersey-client</artifactId>
    <version>2.17</version>
</dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-jetty-servlet</artifactId>
            <version>2.16</version>
        </dependency>

    </dependencies>

</project>

Project Structure :

 

use rest console with

Url:

http://localhost:8080/JerseyDemo/rest/user

Method :

Post

And header param

token = java

How to use retailAll in LinkedList

Retains only the elements in this list that are contained in the specified collection. In other words, removes from this list all of its elements that are not contained in the specified collection.


import java.util.LinkedList;
import java.util.List;

public class RetainAll {

    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println(" Linklist is = "+linkedList);
       
        List<String> brr = new LinkedList<String>();
       
        brr.add("Delhi");
        brr.add("KKR");
       
        /*
         * Retains only the elements in linkedlist
         * collection that are contained in the brr
         */
       
       
        linkedList.retainAll(brr);
       
        System.out.println("After retainAll linkedlist is= "+linkedList);
       
       
    }
   
   
}

Output:

 Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

 After retainAll linkedlist is= [Delhi]

How to insert element in LinkedList

we can insert element in Linkedlist at a given index.for this we use add(int index,element).

import java.util.LinkedList;

public class AddElement {
   
    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println(" Linklist is = "+linkedList);
       
        /*
         * Inserts the specified element at the specified position
           in this list. Shifts the element currently at that position
           (if any) and any subsequent elements to the right
         */
       
        linkedList.add(2, "bangalore");
       
        System.out.println("After Insert Element Linkedlist is = "+linkedList);
       
    }

}

Output:

 Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

After Insert Element Linkedlist is = [Mumbai, Delhi, bangalore, Noida, Gao, Patna]
 

How to replace element in LinkedList

 We can replace any specific index element by other element using set(int index,element) method.


import java.util.LinkedList;

public class ReplaceElement {

    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println("Before Replace Element Linklist is = "+linkedList);
       
        /*
         * Replaces the element at the specified position in
         * this list with the specified element.
         */
       
        linkedList.set(2,"chandigarh");
       
        System.out.println("After Replace Element Linklist is = "+linkedList);
       
    }   
   
}

Output:

Before Replace Element Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

After Replace Element Linklist is = [Mumbai, Delhi, chandigarh, Gao, Patna]
 

How to count number of element in LinkedList

Size() Method return number of element in the LinkdeList .

import java.util.LinkedList;

public class CountElement {
   
    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println("Before Remove Element Linklist is = "+linkedList);
       
        //Returns the number of elements in this list.
        System.out.println("number of element in linkedlist = "+linkedList.size());
       
    }

}


Output:

 Before Remove Element Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

 number of element in linkedlist = 5

How to shuffle elements in LinkedList

import java.util.Collections;
import java.util.LinkedList;

public class Shuffle {

    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println("Linklist is = "+linkedList);
       
        //Randomly permutes the specified list using a default
         //source of randomness.
       
        Collections.shuffle(linkedList);

        for (String str : linkedList) {
            System.out.println(str);
        }
   
        Collections.shuffle(linkedList);
       
        System.out.println("After Second Shuffle");
       
        for (String str : linkedList) {

            System.out.println(str);

        }
       
    }   
   
}

Output:

Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

Gao
Noida
Mumbai
Patna
Delhi

After Second Shuffle

Noida
Patna
Gao
Mumbai
Delhi

How to find does LinkedList contains elements or not

Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that (o==null ? e==null : o.equals(e)).


import java.util.LinkedList;

public class ContailsElement {

    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
        //print linkedlist
        System.out.println(" Linklist is = "+linkedList);
       
        //Returns true if this list contains the specified element
       
        System.out.println(linkedList.contains("Delhi"));
       
        System.out.println(linkedList.contains("panjab"));
       
    }
   
}

Output:

 Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

 true

 false

How to get element of LinkedList

We  use method  get(int index) for get any element at specific index.

import java.util.LinkedList;

public class GetElement {
   
    public static void main(String[] args) {
       
        LinkedList<String> linkedList = new LinkedList<String>();
       
        linkedList.add("Mumbai");
        linkedList.add("Delhi");
        linkedList.add("Noida");
        linkedList.add("Gao");
        linkedList.add("Patna");
       
        //print linkedlist
        System.out.println("Before Remove Element Linklist is = "+linkedList);
       
        System.out.println("Element At Index 2 ="+linkedList.get(2));
       
    }

}

 Output:

Before Remove Element Linklist is = [Mumbai, Delhi, Noida, Gao, Patna]

Element At Index 2 =Noida