Implicit and Explicit Constructor Chaining

Constructor chaining in Java is simply the act of one constructor calling another constructor via inheritance. This happens implicitly when a subclass is constructed: its first task is to call its parents constructor method. But programmers can also call another constructor explicitly using the keywords  this() or  super(). The this() keyword calls another overloaded constructor  in the same class; the super() keyword calls a non-default constructor in a superclass. Implicit Constructor Chaining Constructor chaining occurs through the use of inheritance. A subclass constructor methods first task is to call its superclass constructor method. This ensures that the creation of the subclass object starts with the initialization of the classes above it in the inheritance chain. There could be any number of classes in an inheritance chain. Every constructor method calls up the chain until the class at the top has been reached and initialized. Then each subsequent class below is initialized as the chain winds back down to the original subclass. This process is called constructor chaining. Note that: This implicit call to the superclass is the same as if the subclass had included the super() keyword, i.e. super() is implicit here.If a no-args constructor is not included in the class, Java creates one behind the scenes and invokes it. This means that if your only constructor takes an argument, you must explicitly use a this() or super() keyword to invoke it (see below). Consider this superclass Animal extended by Mammal: class Animal {// constructorAnimal(){   System.out.println(Were in class Animals constructor.);}} class Mammal extends Animal {//constructorMammal(){   System.out.println(Were in class Mammal s constructor.);}} Now, lets instantiate the class Mammal: public class ChainingConstructors {   /*** param args*/public static void main(String[] args) {Mammal m new Mammal();}} When the above program runs, Java implicitly triggers a call to the superclass Animal constructor, then to the class constructor. The output, therefore, will be: Were in class Animals constructorWere in class Mammals constructor Explicit Constructor Chaining using this() or super() Explicit use of the this() or super() keywords allows you to call a non-default constructor. To call a non-args default constructor or an overloaded constructor from within the same class, use the  this()  keyword.  To call a non-default superclass constructor from a subclass, use the super() keyword. For instance, if the superclass has multiple constructors, a subclass may always want to call a specific constructor, rather than the default. Note that the call to another constructor must be the first statement in the constructor or Java will throw a compilation error. Consider the code below in which a new subclass, Carnivore, inherits from Mammal class which inherits from the Animal class, and each class now has a constructor that takes an argument. Heres the superclass Animal:   public class Animalprivate String name;public Animal(String name)  // constructor with an argument{this.name name;System.out.println(Im executed first.);}}Note that the constructor now takes a name of type String as a parameter and that the body of the class calls this() on the constructor. Without the explicit use of this.name, Java would create a default, no-args constructor and invoke that, instead. Heres the subclass Mammal: public class Mammal extends Animal {public Mammal(String name){super(name);System.out.println(Im executed second);}} Its constructor also takes an argument, and it uses super(name) to invoke a specific constructor in its superclass. Heres another subclass Carnivore. This inherits from Mammal:   public class Carnivore extends Mammal{public Carnivore(String name){super(name);System.out.println(Im executed last);}} When run, these three code blocks would print: Im executed first.Im executed second.Im executed last. To recap: When an instance of the Carnivore class is created, the first action of its constructor method is to call the Mammal constructor method. Likewise, the first action of the Mammal constructor method is to call the Animal constructor method. A chain of constructor method calls ensure that the instance of the Carnivore object has properly initialized all the classes in its inheritance chain.

Library Learning Activities BIO 107 (ANATOMY PHYSIOLOGY) Article

Essays on Simulating the Decentralized Processes of the Human Immune System in a Virtual Anatomy Model by Sarpe and Jacob Article The paper "Simulating the Decentralized Processes of the Human Immune System in a Virtual Anatomy Model by Sarpe and Jacob" is a great example of a biology article. Problem statement: the article discusses simulations that take place in the decentralization of processes of the human immune system as to be in a virtual anatomy model.   Processes in the human biological system can be explained using models of large systems. The research focuses on the physical perspectives of the immune processes of human beings. The complexity of the immune system has always been a challenge to explain without referring to the spatial distribution of organs that relate to it. The research has incorporated different prototypes into one simulation of immune processes (Sarpe Jacob, 2013). It has presented methodologies and modeling to depict a simulation system that is agent-based. The agents in the model include viruses, cytokines, and immune cells. In this case, the system interacts with its components in two different ways which include inside a lymph node and within the tissue.The variables in the research are factors that make up the immune system. There is a clear description of how agents of the system interact. The research finds that agent-based simulations relate to the current simulations on human body immunity. The resear ch has proved that the model can be used to demonstrate how connected simulations occur (Sarpe Jacob, 2013). The situation can be prevented through the use of a network of computers. The research will have a positive impact on my profession. The model can be used as a tuning technique on the study of the immune system to help in understanding the processes. It would help in advancing the understanding of the immune system of the human body.

Analysis and Critique on French Education System Free Essays

In my opinion, the French education system is faulty and undeserving. Meisler portrays for us in animated detail, the torture that French pupils go through in their schooldays. It is also relatively easy for me to understand this scenario because in my country, India, the scene is strikingly similar. We will write a custom essay sample on Analysis and Critique on French Education System or any similar topic only for you Order Now It is also the reason that I am here right now–in the United States getting the benefits of the best undergraduate system in the world–to take home with me the accrual of a â€Å"liberal† education. I find the lack of French students in an American institution surprising. Surely French parents will think and re-think before making a choice between their child†s future and the haughtiness of their country†s culture. Do they really want risk their children to go through a system where the chance of getting the baccalaureate degree is only one in three? What is the point of â€Å"attempting† to get an education? The country†s literacy rate reads ninety-nine percent yet Meisler indicates that two-thirds of France is without a reputed degree. These statistics are unheard of in the rest of the world. Students who do manage to get this degree get celebrity treatment and many go on to become Nobel laureates. Nevertheless, what of those who not make it? They live an obscure life, affected by their failure until their dying day. This also happens to be the reason for France†s contemptuous behavior towards tourists. One often comes across a French waiter or low-level bureaucrat or store clerk behaving defensively as they had done with their teachers, desperately trying to evade disapproval. Fear being their motivation rather than the pursuit of success. French education seemingly preaches that France is the world and that there is nothing beyond. Meisler has pointed out a symbolic example when he says that, in English, people usually try to judge the level of comprehension of the person with whom they are conversing. They then try to adapt to the same wavelength so that the conversation carries on with least difficulty. However, to the French, this is an alien concept. If you cannot speak the perfect grammar that they as children have been taught in medieval fashion, you become an outcast. I think the French have to modify their philosophy and look beyond defining â€Å"education† as â€Å"academics†. There is much more to a complete education than precision of mind, command of language and a huge store of memory. They have to realize that Nobel laureates do not mean much until they are representatives of their entire country. Although France may have had several more Nobel laureates than the United States, it has achieved this at a price. The price of disregarding their â€Å"lesser† citizens. The United States on the other hand has gone the Darwinian way–the process of natural selection–and has let the people discover themselves and bring the best out in them. They have not had them molded to become superior beings–which in my vocabulary reads as â€Å"robots†Ã¢â‚¬â€œwhich in turn is defined in the Webster dictionary as â€Å"an efficient insensitive person who functions automatically. † The French education system is in desperate need of a complete overhaul. Otherwise, their nation is going to lose all of the little importance that they have in the world today because of their immodesty and arrogance. France is and will be nothing more than an angry yapping poodle in the midst of uninterested, lazing bulldogs. How to cite Analysis and Critique on French Education System, Papers