Skip to main content

Class Loading while running JVM

  • The Order is
    • Bootstrap classes - Classes that comprise the Java platform, including the classes in rt.jar and several other important jar files.
    • Extension classes - Classes that use the Java Extension mechanism. These are bundled as .jar files located in the extensions directory.
    • User classes - Classes defined by developers and third parties that do not take advantage of the extension mechanism. You identify the location of these classes using the -classpath option on the command line (the preferred method) or by using the CLASSPATH environment variable. 
Labels:

Popular posts from this blog

Primitive Obsession with Example

Primitive Obsession is the name of a code smell that occurs when we use primitive data types to represent domain ideas. For example, we use a string to represent a message or an integer to represent an amount of money. For Example: Code with Primitive Obsession // primitiveObsession.java public class primitiveObsession { public static void main ( String args []) { Integer [] cityPopulations = { 13000000 , // London 21903623 , // New York 12570000 , // Tokyo 1932763 , // Stockholm 1605602 , // Barcelona 4119190 // Sydney }; for ( Integer cityPopulation : cityPopulations ) { System . out . println ( cityPopulation ); } } } public class City { private final String name ; private final int population ; private final Continent continent ; public String getName () { return name ; } public int getPopulation () { return population ; } public Continent ge...
Read more

Singleton Pattern

Lazy Initialization :- The instantiation of an object can be delayed until it is actually needed. Usage: This especially beneficial when the constructor is doing a costly job like, accessing a remote database. Example: This code demonstrates how the Singleton pattern can be used to create a counter to provide unique sequential numbers, such as might be required for use as primary keys in a Database:   Sequence.java   public class Sequence { private static Sequence instance; private static int counter; private Sequence() { counter = 0; // May be necessary to obtain // starting value elsewhere... } public static synchronized Sequence getInstance() { if(instance==null) // Lazy instantiation { instance = new Sequence(); } return instance; } public static synchronized int getNext() { return ++counter; } }   Some things to note about this implementation: Synchronized methods are used to ensure that the class is thread-safe. This class cannot be subclassed because the constructor is private ...
Read more

MVC Design Patterns

Context MVC is an architectural pattern that is used when developing interactive application such as a shopping cart on the Internet. Problem User interfaces change often, especially on the internet where look-and-feel is a competitive issue. Also, the same information is presented in different ways. The core business logic and data is stable . Solution Use the concept of dividing the concerns to divide the application into three areas Model :- Encapsulates the core data and the functionality View :- Encapsulates the presentation of the data there can be many views of the common data Controller:- accepts input from the user and makes request from the model for the data to produce a new view The model represents the structure of the data and the operations that can be performed on that data. The view represents the data that is in a presentable format. The controller translates the user action like mouse events, submit, keystrokes, words spoken with user input to call the call t...
Read more