Very Impotent Links for Java and Portal development development

1. Jar Download for Spring 
2. Maven Or Gradel Dependency for Spring 

List of Importent software required to be downloaded free of cost

My Personal Notes

SpringMVC

Failed to load the jni shared library jvm.dll

To resolve “failed to load the jni shared library jvm.dll” issue and to run eclipse in 64 bit Windows Successfully you need following things.

·         64 bit Windows Operating System.

·         64 bit Java.

·         64 bit Eclipse.

I am sure you have 64 bit of Windows. Please download Java and Eclipse from link given below.

·         Download 64 bit Java from here.

·         Download 64 bit Eclipse from here.

Try to run eclipse again, “failed to load the jni shared library jvm.dll” won’t be there.

Difference between Array And ArrayList

Difference between Array And ArrayList

SR	Array	ArrayList
1	Array has a fixed length	it will grow as you ad elements to it
2	Array can store value  must be of similar data type  .	ArrayList value  may be differ it can store any object value
3	store value in contiguous memory location	store value in contiguous memory location
4	Array start with a index of 0	ArrayList start with a size of 0
5	In an array you have to track down yourself how many elements are in the array	you can always know how many elements contains an ArrayList by calling it's size() method
6	It does not Shrink	when you remove an element from an ArrayList it shrinks automatically

Iterator ListIterator and Enumeration

Iterator ListIterator and Enumeration

SR	Iterator	List Iterator	Enumeration
1	iterator was introduced after Enumerator		Enumeration is older and its there from JDK1.0
2	is Iterator has a remove() method	is ListIterator has a remove() method	while Enumeration doesn't.
3	Iterator we can manipulate the objects like adding and removing the objects from collection e.g. Arraylist.		Enumeration acts as Read-only interface, because it has the methods only to traverse and fetch the objects,
4	Iterator is more secure and safe as compared to Enumeration because it  does not allow other thread to modify the collection object while some thread is iterating over it and throws ConcurrentModificationException.	ListIterator is more secure and safe as compared to Enumeration because it  does not allow other thread to modify the collection object while some thread is iterating over it and throws ConcurrentModificationException	Less secure as compared to Iterator
5	Iterator interface methods: hasNext() next() remove()	LisIterator hods: hasNext() next() remove() hasPrevious() previous()	Enumeration hasMoreElement() nextElement() N/A
6	We can iterate only in one direction .	We can iterate in both direction .	We can iterate only in one direction .
7	Iteration can be done only once. If you reach the end of series its done. If we need to iterate again we should get a new Iterator.	New ListIterator is not required	Enumeration can be done only once. If you reach the end of series its done. If we need to iterate again we should get a new E.numerator
8		The interface Java.util.ListIterator extends java.util.Iterator interface.
9	public class Test { public static void main (String args[]) { List<String> list =new  ArrayList(); list.add("01"); list.add("02"); list.add("03"); list.add("04"); Iterator LS= list.Iterator(); while (LS.hasNext()) { String s=(String) LS.next(); System.out.println(s); } } }	public class Test { public static void main (String args[]) { List<String> list =new  ArrayList(); list.add("01"); list.add("02"); list.add("03"); list.add("04"); ListIterator LS= list.listIterator(); while (LS.hasNext()) { String s=(String) LS.next(); System.out.println(s); } } }	public class Test { public static void main (String args[]) { List<String> list =new  ArrayList(); list.add("01"); list.add("02"); list.add("03"); list.add("04"); //get the Enumeration object    Enumeration e = Collections.enumeration(list);       //enumerate through the ArrayList elements    System.out.println("Enumerating through Java ArrayList");    while(e.hasMoreElements()){  System.out.println(e.nextElement());    } } }

Why clone method not visible in all of our class even we know that Object class is parent of all classes

Why  clone method not visible in all of our class  even we know that Object class is parent of all classes

→ When a protected member is inherited across package it becomes private member of inherited class

→ when a protected member is inherited within the same package it becomes default member of inherited class.

→  clone() from Object class is inherited into MyClass across package. Object class is in java.lang package and MyClass is in GoodQuestions package. So clone() method becomes a private member of MyClass class.

That explains why you are unable to access clone() method from TestSingleTon class.