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No; that is the default. In other words, if you don't add "extends", the class will automatically inherit from the "Object" class.
No; that is the default. In other words, if you don't add "extends", the class will automatically inherit from the "Object" class.
No; that is the default. In other words, if you don't add "extends", the class will automatically inherit from the "Object" class.
No; that is the default. In other words, if you don't add "extends", the class will automatically inherit from the "Object" class.
What else can I help you with?
What is class hierarchies in java?
The top level class in Java is class Object. Every other class inherits from Object and therefore Object is the top most in the class hierarchy. If you extend a class from Object such as class Animal and further extend Animal with class Dog then the hierarchy is as follows: Object | Animal | Dog Code for this hierachy is as follows: class Animal { } class Dog extends Animal { } We don't need to write class Animal extends Object because every class extends from Object so it does not need to be stated.
Difference between object declaration and object creation?
Declaration of the object involves only creating the reference variable to the object. Example: class SampleClass{ } Object Declaration: SampleClass obj1; Object Creation: Creating an object involves use of new keyword and actually allocating memory for that object. SampleClass obj2 = new SampleClass ();
Can you pass object as an argument to a method?
if you have a function or a method that takes Object as a parameter, you can call that function or method and pass an Object as follows: Let's say you have a class that extends Object and a function as follows public class A extends Object { ..... } void function ( A arg ){ ..... } To call this function, you need an instance of the class A A objectInstance = new A(); function(objectInstance); The next line shows how to pass an instance of the class A to the function.
In what order are the class constructors called when a derived class object is created?
We know that constructors are invoked at runtime when you say new on some class type as follows: Lamborghini h = new Lamborghini(); But what really happens when you say new Lamborghini() ? (Assume Lamborghini extends Car and Car extends Object.) 1. Lamborghini constructor is invoked. Every constructor invokes the constructor of its superclass with an (implicit) call to super(), 2. Car constructor is invoked (Car is the superclass of Lamborghini). 3. Object constructor is invoked (Object is the ultimate superclass of all classes, so class Car extends Object even though you don't actually type "extends Object" into the Car class declaration. It's implicit.) At this point we're on the top of the hierarchy. 4. Object instance variables are given their explicit values. By explicit values, we mean values that are assigned at the time the variables are declared, like "int x = 27", where "27" is the explicit value (as opposed to the default value) of the instance variable. 5. Object constructor completes. 6. Car instance variables are given their explicit values (if any). 7. Car constructor completes. 8. Lamborghini instance variables are given their explicit values (if any). 9. Lamborghini constructor completes.
Class hierarchy is a fundamental concept of object oriented programs explain what this term means with reference to inheritance abstraction and instantiation?
Class hierarchy is a term used in Java. It is used for identifying the inheritance hierarchy or the parent class relationships Ex: Public class B extends C { } Public class A extends B { } Here if we take the class hierarchy for class 'A' it would be A
What is class hierarchies in java?
The top level class in Java is class Object. Every other class inherits from Object and therefore Object is the top most in the class hierarchy. If you extend a class from Object such as class Animal and further extend Animal with class Dog then the hierarchy is as follows: Object | Animal | Dog Code for this hierachy is as follows: class Animal { } class Dog extends Animal { } We don't need to write class Animal extends Object because every class extends from Object so it does not need to be stated.
What is hierarchy in java?
The top level class in Java is class Object. Every other class inherits from Object and therefore Object is the top most in the class hierarchy. If you extend a class from Object such as class Animal and further extend Animal with class Dog then the hierarchy is as follows: Object | Animal | Dog Code for this hierachy is as follows: class Animal { } class Dog extends Animal { } We don't need to write class Animal extends Object because every class extends from Object so it does not need to be stated.
Difference between object declaration and object creation?
Declaration of the object involves only creating the reference variable to the object. Example: class SampleClass{ } Object Declaration: SampleClass obj1; Object Creation: Creating an object involves use of new keyword and actually allocating memory for that object. SampleClass obj2 = new SampleClass ();
Can you pass object as an argument to a method?
if you have a function or a method that takes Object as a parameter, you can call that function or method and pass an Object as follows: Let's say you have a class that extends Object and a function as follows public class A extends Object { ..... } void function ( A arg ){ ..... } To call this function, you need an instance of the class A A objectInstance = new A(); function(objectInstance); The next line shows how to pass an instance of the class A to the function.
Is constructor created automatically in java?
There is a default constriuctor that takes no argument for every class that extends Object.
Write a program to demonstrate multilevel inheritence in java?
Ex: public class A { ... } public class B extends A { ... } public class C extends B { ... } Here class C extends B which in turn extends A so class C indirectly extends class A.
Example of single inheritance in java?
Any class you create will inherit from another class - either explicitly, if you use the extends keyword, or implicitly from the Object class. This is single inheritance, since you can't inherit from more than one class. Here are two examples:public class MyClassA{...}public class MyClassB extends MyClassA{...}In the above examples, MyClassA implicitly inherits from Object, and MyClassB explicitly inherits from MyClassA.
In what order are the class constructors called when a derived class object is created?
We know that constructors are invoked at runtime when you say new on some class type as follows: Lamborghini h = new Lamborghini(); But what really happens when you say new Lamborghini() ? (Assume Lamborghini extends Car and Car extends Object.) 1. Lamborghini constructor is invoked. Every constructor invokes the constructor of its superclass with an (implicit) call to super(), 2. Car constructor is invoked (Car is the superclass of Lamborghini). 3. Object constructor is invoked (Object is the ultimate superclass of all classes, so class Car extends Object even though you don't actually type "extends Object" into the Car class declaration. It's implicit.) At this point we're on the top of the hierarchy. 4. Object instance variables are given their explicit values. By explicit values, we mean values that are assigned at the time the variables are declared, like "int x = 27", where "27" is the explicit value (as opposed to the default value) of the instance variable. 5. Object constructor completes. 6. Car instance variables are given their explicit values (if any). 7. Car constructor completes. 8. Lamborghini instance variables are given their explicit values (if any). 9. Lamborghini constructor completes.
Can object extends?
objects are instances of class only and moreover objects are object reference variables extension of variables is meaningless so objects in java can't be extend
Class hierarchy is a fundamental concept of object oriented programs explain what this term means with reference to inheritance abstraction and instantiation?
Class hierarchy is a term used in Java. It is used for identifying the inheritance hierarchy or the parent class relationships Ex: Public class B extends C { } Public class A extends B { } Here if we take the class hierarchy for class 'A' it would be A
How can you access the super class variables with out any object creation?
Variables of the super class can be accessed using the super keyword. Here is an example. class A { int a; } class B extends A { int a; public B() { super.a = 5; } }
Specification forms of inheritance in java?
single level inheritance eg ( class B extends Class A) Multilevel inheritance eg( class C extends class B and class B extends class A) multiple inheritance Class C inherits Class A features as well as Class B featues.This type of inheritance is not allowed in JAVA.
