Why do classes have multiple constructors?
To put it simply, you use multiple constructors for convenience (1st example) or to allow completely different initialization methods or different source types (2nd example. When a Java class contains multiple constructors, we say that the constructor is overloaded (comes in multiple versions).
What happens if you write constructor more than once in a class?
The intent of constructors is to create the object, so each time you use the new operator, the constructor is called and a new object is created. You can not call the constructor directly.
Is it possible to call a constructor from another within the same class not from a subclass )? If yes how?
Yes, any number of constructors can be present in a class and they can be called by another constructor using this() [Please do not confuse this() constructor call with this keyword]. this() or this(args) should be the first line in the constructor. This is known as constructor overloading.
How do you call a constructor from another constructor in the same class?
To call one constructor from another constructor is called constructor chaining in java. This process can be implemented in two ways: Using this() keyword to call the current class constructor within the “same class”. Using super() keyword to call the superclass constructor from the “base class”.
Will a class contain multiple constructors?
A class can have multiple constructors, as long as their signature (the parameters they take) are not the same. You can define as many constructors as you need. This is what constructor overloading means, that a Java class contains multiple constructors.
Can a constructor be called from a method?
If so, just use new Object ();. The constructor will be called for the new object. You cannot call constructors from methods, you can call constructors only from other constructors using this or super keywords. You can only call a constructor once, and it has to be the first statement in your constructor body.
What happens if you call the last constructor without parameters?
If you call the method without parameters, it can internally call the method with parameters, to keep your code non-redundant. I expected this to be also true for constructors. In this example, the last constructor is working as expected. The other constructors only return objects without set values.
How often can you call a constructor in Java?
You can only call a constructor once, and it has to be the first statement in your constructor body. If you do not call any constructor from a contructore body java compiler will implicitly insert super () statement into the constructor