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What is use of constructor in java?
Constructor is used to do something (written in constructor) immediately after object creation.
Does Java support copy constructor?
No. Java does not support copy constructor
What happens when no constructor function is declared in a class - in Java?
When any constructor is deffined in your class, the java compiler create a default no argument constructor for you. This constructor only have an invocation to the super class constructor (" super( ) ").
What is a constructor and its mandatory to use constructor in a class?
A constructor is a method that is invoked when an object is created. As to being mandatory, that really depends on the programming language; in the case of Java, each class must have a constructor, however, in many cases Java will automatically provide a default constructor, so you don't really need to program it.
Is there a sample program for constructor?
All Java programs would have a constructor... public class Test { public Test(){ ... } ..... } This is a constructor. Even if you dont code the constructor Java would automatically place a default constructor for compilation.
Can you use constructor in servlet?
Yes you can but it is not required. A Servlet is nothing but another .java file and all rules that are applicable to standard Java classes are applicable to them. Note: Even if you write a constructor in a servlet, it will not get executed.
Why Java always provides a default constructor to class when you use another constructor default constructor remove?
Classes in Java inherit constructors from their parent classes. If you don't explicitly define a parent class, then Object is used, which has only the default empty constructor. That "default" constructor is only there when defined by the parent class, so classes which do not have a no-argument constructor will not allow subclasses to automatically use it. This is implemented this way because of the special nature of constructors. Java could not always provide a default constructor because it could not guarantee that all class members would be properly created or initialized.
Can you initialize an object without constructor in java?
No. if you wish to create an object that you plan on using in a java program then the answer is NO. You cannot initialize an object of a Java class without calling the constructor.
Can a constructor be defined within a method in java?
No.
Why constructor rather than classes in java?
Constructor is not an alternative to class. In Java, you create classes; the classes contain methods - including the constructor, which can be viewed as a special method. If you want to have a constructor, you need a class that surrounds it, so it's not one or the other.
What is copy constructor in java?
Java, unlike C++ does not support copy constructors.
Can you create a constructor for an interface in java?
NO, we cannot create a contructor for an interface in java.
Can you use business logic in constructor with example in java?
No. Logic should never go in a constructor; constructors should only be used to instantiate and initialize object data.
How many kinds of constructor in java?
Java has 2 types of constructors based on parameters passed:Default or parameter-less constructor: A constructor which does not accept any arguments.Parametrized constructor: A constructor which accepts one or more arguments.Similarly based on Access modifier also we have:Public constructor - Class can be instantiated by anyonePrivate constructor - Class cannot be instantiated by anyoneProtected constructor - Class can be instantiated only by sub classes
What does it mean in java when a constructor is undefined?
When a constructor is not define in java then the instance used in class is not optimised the value and therefore some times it generates some garbage value. By the way , When we not define a constructor then generally it not distrub the execution of the program.
What is the function of this in java?
this in java is a keyword that refers to the current object of the class. It is also used in constructor overloading when you want to invoke one constructor from another within the same class.
Can you overload the constructor in java true or false?
Yes, you can have more than one constructor with a different set of parameters.
Why constructor in Java doesn't have any return type?
The constructor of a Java class is not an ordinary method. Its purpose is not to return any value. The purpose of the constructor is to instantiate the class which it does. Since, the purpose of a constructor is only to instantiate and initialize its class and not anything else, it does not have a return type. All it does is creates an object of that class.
What is a constructoris it mandatory to use constructor in a class?
You always should define default constructor for your class. You must also define a copy constructor for your class if there are any pointers in the class. While it is not mandatory, failure to provide a default constructor can result in bad behavior, and failure to provide a copy constructor when you have pointers in the class will result in bad behavior. For example, without a default constructor, the compiler will not fully initialize the attributes of the class. It will initialize the virtual function table, and call base class constructors, but that is all - the attributes could be random garbage. For another example, without a copy constructor, the compiler will generate one that simply makes a bit wise copy of the attributes. If these attributes contain pointers, then you have two pointers to the same object, not necessarily a good thing, especially if one of them get "deleted".
How many constructor can be defined in a classin java p rogramming?
how many constructer can be defined in class in overloading of java programming
