PHP allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is suitable for any initialization that the object may need before it is used. Note : Parent constructors are not called implicitly if the child class defines a constructor. If the child does not define a constructor then it may be inherited from the parent class just like a normal class method if it was not declared as private. Constructors are ordinary methods which are called during the instantiation of their corresponding object.
Constructor Overloading in Java: What is & Program Examples
Destructor Contrary to the constructor, when the object ends its life cycle for example, the function where the object is called , the system automatically executes the destructor. Destructors are often used to do "clean up" for example, when creating an object, use new to open up a memory space, delete will automatically call the destructor and release the memory. It cannot take any arguments, nor does it return a value including the void type. There can only be one destructor and it cannot be overloaded. If the user does not write a destructor, the compilation system will automatically generate a default destructor even if the destructor is customized, the compiler will always synthesize a destructor for us, and if the custom destructor The function, the compiler will call the custom destructor and then call the synthesized destructor when it executes, and it will not do anything. So there are no explicit destructors in many simple classes.
As you all know that all objects that are created must be given initial values which can be done in two ways. The first way of doing this is to use the dot operator to access the instance variable and then to assign values to them individually. It can be a tedious approach to initialize all the variables of the object in this manner.
In Java, when we create an object of the class it occupies some space in the memory heap. If we do not delete these objects, it remains in the memory and occupies unnecessary space that is not upright from the aspect of programming. To resolve this problem, we use the destructor. In this section, we will discuss the alternate option to the destructor in Java.