String Reverse This tutorial will show you string reverse example in Java. You can use various ways to reverse a string in Java and I have presented here five ways to reverse a string. String class in Java is an immutable class and that’s why it does not have reverse() method to reverse the given string. I will use here…

Introduction Here in this post I will discuss how singleton pattern works in Java. Singleton pattern is a design solution, where an application wants to have one and only one instance of a class, in all possible scenarios without any exceptional condition. The singleton instance is actually created per JVM but not across multiple JMVs. The singleton class has a…

Introduction HashMap (also known as HashTable) is, a data structure that can map keys to values, used to implement an associative array. A HashMap uses a hash function to compute an index into an array of buckets or slots, from which the correct value can be found. Ideally, the hash function will assign each key to a unique bucket, but…

Introduction Here I will discuss how to override equals() and hashCode() methods in Java. In Java language the important contract is whenever you override one of the methods (equals() and hashCode()), then you must override the other method. So it means that when you override method equals() then you must override hashCode() or vice versa.

RSA Encryption/Decryption RSA is a cryptosystem, which is known as one of the first practicable public-key cryptosystems and is widely used for secure data transmission. In such a cryptosystem, the encryption key is public and differs from the decryption key which is kept secret. In RSA, this asymmetry is based on the practical difficulty of factoring the product of two…

Introduction In this post we will see how to cache static resources like css, js and images for a specific period of time. So we will specify the time for how long we want to cache such static resources. Static resources like css, js images etc. need not be reloaded from the server every time until and unless we want…