Daily Archives: August 22, 2012

Effect of extends and Object over constructor and parent class

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How Static and Constructor will work when class is Extended

  public class Main2 extends A   
  {
   public static void main(String args[])
    {	
	   
    }
  }

  class A extends B 
  {
    A()
    {
      System.out.println("I am A Constrctor");
    }
	
    static
   {
      System.out.println("I am Static Method");
   }
	
   {
      System.out.println("Empty");
   }
 }

 class B
 {
   B()
   {
     System.out.println("I am B Constrctor");
   }
 }

OP:I am Static Method

How Static and Constructor will work when class object is Created

   public class Main2 extends A   
  {
   public static void main(String args[])
    {	
       A objA = new A();  
    }
  }

  class A extends B 
  {
    A()
    {
      System.out.println("I am A Constrctor");
    }
	
    static
   {
      System.out.println("I am Static Method");
   }
	
   {
      System.out.println("Empty");
   }
 }

 class B
 {
   B()
   {
     System.out.println("I am B Constrctor");
   }
 }

OP:I am Static Method
I am B Constrctor
Empty
I am A Constrctor

How to store CSV in hidden Field Javascript

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How to Store CSV Ids in Hidden Field
Script

function AddProjectId(pProjectId) 
{
    var arrProjectIds = new Array();
    var strComma = '';
    csvProjectIds = $('#hdnInterestedProjectIds').val();
    csvProjectIds = $.trim(csvProjectIds);
    
    if (csvProjectIds != '') 
    {
        arrProjectIds = csvProjectIds.split(', ');
        lngArrLength = arrProjectIds.length;
    } else {
        lngArrLength = 0;
    }
    
    if (arrProjectIds.indexOf(pProjectId) != 0) {
        if (lngArrLength > 0)
            strComma = ', ';
        csvProjectIds = csvProjectIds + strComma + pProjectId;
    }
    
    $('#hdnInterestedProjectIds').val(csvProjectIds);
}

function RemoveProjectId(pProjectId) 
{
    csvProjectIds = $('#hdnInterestedProjectIds').val();
    csvNewProjectIds = '';
    arrProjectids = csvProjectIds.split(', ');
    arrNewProjectIds = new Array();
    lngArrLength = arrProjectids.length;
    
    for (i = 0; i < lngArrLength; i++) 
    {
        if (arrProjectids[i] != pProjectId) 
        {
            arrNewProjectIds.push(arrProjectids[i]);
        }
    }
    
    for (i = 0; i < arrNewProjectIds.length; i++) 
    {
        strComma = '';
        
        if ((csvNewProjectIds != '') && (arrNewProjectIds.length != (arrNewProjectIds.length - 1)))
            strComma = ', ';
        
        csvNewProjectIds = csvNewProjectIds + strComma + arrNewProjectIds[i];
    }
    
    $('#hdnInterestedProjectIds').val(csvNewProjectIds);
}

<input type=”hidden” name=”hdnInterestedProjectIds” id=”hdnInterestedProjectIds”/>

Working with javascript Arrays

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How to Split CSV into array 

   csvProjectIds = '1,2,3,4';
   arrProjectIds = csvProjectIds.split(',');

Output

     arrProjectIds[0] = 1
     arrProjectIds[1] = 2
     arrProjectIds[2] = 3
     arrProjectIds[3] = 4

How to Find Element is in Array

   csvProjectIds = '1,2,3,4';
   arrProjectIds = csvProjectIds.split(',');				
   alert(arrProjectIds.indexOf('1'));

Output

 0

The indexOf Returns 0 incase the element is in the array or
-1 if not in the array

Initiation Order

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What would be the Output

public class Main 
{	
  static
  {
    System.out.println("My Name is Mugil");
  }
}

OP: My Name is Mugil
followed by exception in Main

public class Main 
{	
  static
  {
    System.out.println("My Name is Mugil");
  }
	
  public static void main(String args[])
  {
    {
      System.out.println("What is your Name");	 
    }
  }
}

OP: My Name is Mugil
What is your Name

public class Main 
{	
  public static void main(String args[])
  {
    {
      System.out.println("What is your Name");
    }
   }
}

OP: What is your Name

4.What is the order they are processed

public class Main 
{	
 public static void main(String args[])
 {
   {
     ClassA objA = new ClassA();
     System.out.println("What is your Name"); 
   }
 }
}

class ClassA 
{
  static
  {
    System.out.println("I am in ClassA Static");
  }
	
  ClassA()
  {
    System.out.println("I am in ClassA Constrctor");  
  }

  {
    System.out.println("I am in ClassA");
  }
}

OP:I am in ClassA Static
I am in ClassA
I am in ClassA Constrctor
What is your Name

Static blocks are initiated at first followed by Constructor followed by classA and content in empty class.

5.How to Use Object to invoke function in Class

public class Main2
{
 public static void main(String args[])
 {	
   new A().showName();
 }
}

class A 
{
  public void showName()
  {
    System.out.println("Hi there");
  }
}

OP : Hi there

6.How to Find Class of object 

  public class Main3 
  {
   public static void main(String[] args) 
   {
     ClasB objB = new ClasB();
     
     if(objB instanceof ClasB)
     {
       System.out.println(objB.getClass().getName());	
     }		
    }
  }

  class ClasB
  {	
  }