Java (JVM) Memory Model At broad level, JVM Heap memory is physically divided into two parts – Young Generation and Old Generation. Young Generation Young generation is the place where all the new objects are created. When young generation is filled, garbage collection is performed. This garbage collection is called Read more…
One of the biggest confusion in Java programming language is whether java is Pass by Value or Pass by Reference. First of all, we should understand what is meant by pass by value or pass by reference. Pass by Value: The method parameter values are copied to another variable and Read more…
There are many ways to reverse a String in Java. We will see traditional ways and using classes that provide an in-build function. 1. Storing in reverse Order In the above piece of code. We have assigned a char of length of String passed to it. In the loop we are Read more…
Based on my previous posts related to StringBuffer and StringBuilder let’s see the difference. StringBuffer StringBuilder StringBuffer was the only choice for String manipulation till Java 1.4 StringBuilder came into picture from Java 1.5. all of its public methods are synchronized all of its public methods are not synchronized StringBuffer provides Thread safety. StringBuilder Read more…
We will find an answer for the following questions What is StringBuffer Available Constructors Commonly used methods StringBuffer Java StringBuffer class is used to create a mutable (modifiable) string. The StringBuffer class in java is the same as the String class except it is mutable i.e. it can be changed. The Read more…
We will find an answer for the following questions What is StringBuilder Available Constructors Commonly used methods StringBuilder Java StringBuilder class is used to create a mutable (modifiable) string. The Java StringBuilder class is the same as the StringBuffer class except that it is non-synchronized. So its not thread-safe and can’t be Read more…
When a client visits the webapp for the first time, and HttpSession is obtained for the first time the servlet container creates a new HttpSession object, generates a long and unique ID (which you can get by session.getId()), and store it in the server’s memory. The servlet container also sets Read more…
What happens when Rest API is fired? The servlet container is attached to a web server that listens for HTTP requests on a certain port number (port 8080 for development and port 80 in production). When a client (user with a web browser) sends an HTTP request, the servlet container Read more…
What happens behind the scene when Web Application is deployed in Web Server like Tomcat? ServletContext It provides a set of methods that a servlet uses to communicate with its servlet container. There is one context per “web application” per Java Virtual Machine. A “web application” is a collection of servlets Read more…
Based on my previous posts related to Hashtable and HashMap let’s see the difference. HashMap Hashtable Non-Synchronized. Fast. Synchronized. Slow Allows one null key and any number of null values. Hashtable doesn’t allow null keys and null values. Use LinkedHashMap to maintains the insertion order. TreeMap to sort mappings based on the ascending order of Read more…