The below example will show you how to write a simple web based Hello World application using Spring MVC framework. Create a Dynamic Web Application in Eclipse IDE for our Spring Web Application. … [Read more...]
Spring Dependency Injection – Setter Injection
Dependency Injection is the most important concept of the Spring. It is also called as Inversion of Control (IoC). Dependency Injection makes our code Loosely Coupled, Spring’s IOC container is light-weight and it manages the dependency between objects using configurations. It connects the related objects together, instantiates and supplies them based on configuration. Spring … [Read more...]
Difference between ServletConfig and ServletContext
ServletConfig and ServletContext are the two import interfaces in ServletAPI, Lets see whats the difference between them and how to use. ServletConfig ServletConfig is available in the javax.servlet.* package. ServletConfig object will be created during the initialization(init()) of the servlet. … [Read more...]
Polymorphism in Java – Method Overloading and Overriding
Polymorphism is the ability to take more than one form. Polymorphism is one of the most important concept in OOPS ( Object Oriented Programming Concepts). Subclasses of a class can define their own unique behaviors and yet share some of the same functionality of the parent class. In Java, there are 2 ways by which you can achieve polymorphic behavior 1. Method … [Read more...]
How to Create an Immutable Class in Java
Immutable class is the one whose state cannot be changed after it is created. The best example for this is String,Integer class in Java, once instantiated the value never be changed. In this article, lets learn How to Create an Immutable Class in Java. Immutable class has lots of advantages such as they can be used for the caching purposes as you don't need to worry about … [Read more...]
How HashMap works in Java
How a HashMap Works internally has become a popular question in almost all the interview. As almost everybody knows how to use a HashMap or the difference between HashMap and Hashtable. But many fails when the question is how does a hashmap internally works. So the answer to the question how does a hashmap works is that is it works based on the hashing principle but it is … [Read more...]
Difference between HashMap and Hashtable | HashMap Vs Hashtable
Both the HashMap and Hashtable implement the interface java.util.Map but there are some slight differences which has to be known to write a much efficient code. The Most important difference between HashMap and the Hashtable is that Hashtable is synchronized and HashMap is non-synchronized , which means Hashtable is thread-safe and can be shared among multiple threads and … [Read more...]
Difference between Enumeration and Iterator ?
Both Enumeration and Iterator is used for traversing through the underlying Collection. Enumeration can traverse limited collection such as Vectors and HashTable. Whereas Iterator can be used to almost all the Collection. Enumeration is twice as fast as Iterator as it act as read-only interface on the other hand Iterator is much safer as it doesn't allow any modification to the … [Read more...]
Difference between fail-fast and fail-safe Iterator
Difference between fail-fast and fail-safe Iterator has become one of the favorite question for many interviewers as it has a slight flavors of concurrency. Java provides the iterator to iterate the objects in the Collection. The rule is that the Collection should not be altered when iterating, if modified you will get the ConcurrentModificationException. Fail-Fast … [Read more...]
Difference Between Interface and Abstract Class in Java
This is one of the most frequently asked questions in the interview. Many interviewers will not leave this topic. So let's see the difference between them The main difference is that the Interfaces are implicitly abstract and cannot have implementation, whereas an abstract class can have a concrete class. Interface is implemented using the "implements" keyword. Abstract … [Read more...]
Difference between equals() and ==
Both equals() and '==' is used to check the equality of the objects but there is a significant amount of difference between equals() and '=='. The equals method is present in the java.lang.Object class and it is used to check the equivalence of the object (i.,e) to check if the content is equal whereas '==' is used to check if the actual object instances are same or not. … [Read more...]
Sort Objects in a ArrayList using Java Comparable Interface
In my previous post you would have learnt how to sort objects in a ArrayList using java comparator. Using the Comparable interface is almost the same as the previous, but here instead of a separate class for implementing the Comparator interface we can implement it in the same Employee Class by overriding the compareTo() method instead of the compare() method. Let see how the … [Read more...]