- Can a constructor be abstract?
- Is there any copy constructor in Java?
- What is constructor and its types?
- Why can’t a constructor be final?
- Can we override constructor?
- Can abstract class have a constructor in Java?
- What is use of constructor in abstract class in Java?
- Can constructor be static?
- What is purpose of abstract class?
- Can constructor be private?
- Why is copy constructor used?
- Can abstract method have body?
Can a constructor be abstract?
You can’t have an abstract constructor, as abstract means you need to provide the implementation for that at some point of time in your subclass.
But you cannot override constructor.
There will be no point in having an abstract constructor : Since the constructor needs to be of the same name as of class..
Is there any copy constructor in Java?
Generally, the copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously. Java supports for copy constructors but unlike C language, Java does not provide an explicit copy constructor you need to define it yourself.
What is constructor and its types?
A constructor is a special type of function with no return type. Name of constructor should be same as the name of the class. We define a method inside the class and constructor is also defined inside a class. A constructor is called automatically when we create an object of a class.
Why can’t a constructor be final?
A constructor is never inherited to an another class so it doesn’t need to be marked final. Hey, The constructor cannot be final because the constructor cannot be inherited and in constructor values are initialized to the variable so by this variables changes every time and yes it cannot be inherited.
Can we override constructor?
Constructor looks like method but it is not. It does not have a return type and its name is same as the class name. But, a constructor cannot be overridden. If you try to write a super class’s constructor in the sub class compiler treats it as a method and expects a return type and generates a compile time error.
Can abstract class have a constructor in Java?
The constructor inside the abstract class can only be called during constructor chaining i.e. when we create an instance of sub-classes. This is also one of the reasons abstract class can have a constructor.
What is use of constructor in abstract class in Java?
A constructor in Java doesn’t actually “build” the object, it is used to initialize fields. Imagine that your abstract class has fields x and y, and that you always want them to be initialized in a certain way, no matter what actual concrete subclass is eventually created.
Can constructor be static?
A static constructor does not take access modifiers or have parameters. A class or struct can only have one static constructor. Static constructors cannot be inherited or overloaded. A static constructor cannot be called directly and is only meant to be called by the common language runtime (CLR).
What is purpose of abstract class?
The Purpose of Abstract Classes. The purpose of abstract classes is to function as base classes which can be extended by subclasses to create a full implementation. For instance, imagine that a certain process requires 3 steps: The step before the action.
Can constructor be private?
Yes, we can declare a constructor as private. If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.
Why is copy constructor used?
A copy constructor in a Java class is a constructor that creates an object using another object of the same Java class. That’s helpful when we want to copy a complex object that has several fields, or when we want to make a deep copy of an existing object.
Can abstract method have body?
Abstract methods means there is no default implementation for it and an implementing class will provide the details. So, it’s exactly as the error states: your abstract method can not have a body. The reason you would do something like this is if multiple objects can share some behavior, but not all behavior.