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java.io.InputStream
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Which abstract class is the super class of all classes used for writing characters?
java.io.Writer
Can you call an abstract method from a non abstract method in java?
We can't call (i.e, execute) an abstract method in java because these methods don't contain any code to execute!In some special cases like when an abstract method is overridden in a subclass, and when we are using super class reference variable( which is referring that subclass object), it appears that we are calling abstract method in super class. But actually the code in the subclass method is being executed.Example:abstract class SuperClass{abstract void show(); //abstract method in super class}class SubClass extends SuperClass{void show(){ //show() of SuperClass overridden in SubClassSystem.out.println("SubClass Method");}}class Example{public static void main(String... args){SuperClass sup=new SubClass();sup.show(); //SubClass show() will be executed !!!}}
Can abstract class have constructors?
A constructor of a class in invoked when a object of that class is created. As an abstract class can't have an object, so we can't create a constructor of the abstract class. But we can create a constructor of a concrete subclass of that abstract class and we have to pass the object of that concrete subclass to the abstract class.
Real time example for interface vs abstract class in java?
w.frnds........ I am just trying to an example of abstract class and interface class in real life . As these two ["interface class" is not a term in Java programming - just "interface"] classes [sic] are a concept of objest orientation so easy we can easily compare thhese with our real life . Suppose we have an abstract class called clark and an abstract method behabour of this abstract class ,which has no definition in abstract class. two other class security and receptionist inherits these clark class. So in thses two derived class there must has to be a defonation of behabour method,which depends on the derived class which types of behabour they will show........ So that is a real life example of Abstract class .Interface is also same as abstract class only the difference is it can't contain any implementation of any method in base class or super class. I think this is a sufficient example to understand abstract class and interface. [No, it is not sufficient.] If u have any doubt then u can contact me with this email id-rkmahanta26@gmail.com [Interfaces support multiple inheritance; classes do not. Interfaces contain only public members; classes do not have to. Interfaces do not have superclasses, except the implicit 'Object' supertype; they have superinterfaces. Nested interfaces are always static, never inner, unlike classes which can be inner classes. "u" is not an English pronoun. Use the tutorial and the JLS to understand interfaces and abstract classes, not this garbage answer.]
What are the differences between an abstract class and an interface in java?
They are very different. An abstract class is a class that represents an abstract concept (google define "abstract" if you're unsure) such as 'Thoughts' or 'BankAccount'. When a class is defined as abstract it cannot be used (directly) to create an object. Abstract classes are used as super-classes so that all of their subclasses inherit all methods. Interfaces can be thought of as contracts with all of their implementing classes. They simply require all implementing classes to have methods with the same signature as that defined in the interface, but such methods can behave as appropriate. Hope that helps :)
Which abstract class is the super class of all classes used for writing characters?
java.io.Writer
Can you call an abstract method from a non abstract method in java?
We can't call (i.e, execute) an abstract method in java because these methods don't contain any code to execute!In some special cases like when an abstract method is overridden in a subclass, and when we are using super class reference variable( which is referring that subclass object), it appears that we are calling abstract method in super class. But actually the code in the subclass method is being executed.Example:abstract class SuperClass{abstract void show(); //abstract method in super class}class SubClass extends SuperClass{void show(){ //show() of SuperClass overridden in SubClassSystem.out.println("SubClass Method");}}class Example{public static void main(String... args){SuperClass sup=new SubClass();sup.show(); //SubClass show() will be executed !!!}}
Can abstract class have constructors?
A constructor of a class in invoked when a object of that class is created. As an abstract class can't have an object, so we can't create a constructor of the abstract class. But we can create a constructor of a concrete subclass of that abstract class and we have to pass the object of that concrete subclass to the abstract class.
What is the difference abstract class and interface?
They are very different. An abstract class is a class that represents an abstract concept (Google define "abstract" if you're unsure) such as 'Thoughts' or 'BankAccount'. When a class is defined as abstract it cannot be used (directly) to create an object. Abstract classes are used as super-classes so that all of their subclasses inherit all methods. Interfaces can be thought of as contracts with all of their implementing classes. They simply require all implementing classes to have methods with the same signature as that defined in the interface, but such methods can behave as appropriate. Hope that helps :)
Real time example for interface vs abstract class in java?
w.frnds........ I am just trying to an example of abstract class and interface class in real life . As these two ["interface class" is not a term in Java programming - just "interface"] classes [sic] are a concept of objest orientation so easy we can easily compare thhese with our real life . Suppose we have an abstract class called clark and an abstract method behabour of this abstract class ,which has no definition in abstract class. two other class security and receptionist inherits these clark class. So in thses two derived class there must has to be a defonation of behabour method,which depends on the derived class which types of behabour they will show........ So that is a real life example of Abstract class .Interface is also same as abstract class only the difference is it can't contain any implementation of any method in base class or super class. I think this is a sufficient example to understand abstract class and interface. [No, it is not sufficient.] If u have any doubt then u can contact me with this email id-rkmahanta26@gmail.com [Interfaces support multiple inheritance; classes do not. Interfaces contain only public members; classes do not have to. Interfaces do not have superclasses, except the implicit 'Object' supertype; they have superinterfaces. Nested interfaces are always static, never inner, unlike classes which can be inner classes. "u" is not an English pronoun. Use the tutorial and the JLS to understand interfaces and abstract classes, not this garbage answer.]
What are the differences between an abstract class and an interface in java?
They are very different. An abstract class is a class that represents an abstract concept (google define "abstract" if you're unsure) such as 'Thoughts' or 'BankAccount'. When a class is defined as abstract it cannot be used (directly) to create an object. Abstract classes are used as super-classes so that all of their subclasses inherit all methods. Interfaces can be thought of as contracts with all of their implementing classes. They simply require all implementing classes to have methods with the same signature as that defined in the interface, but such methods can behave as appropriate. Hope that helps :)
How do you invoke an overwritten super class from the sub class?
super
Is inheritence in java only based on super class and sub class?
Yes. Inheritance is achieved by using the super class and sub class concept
How is a constructor in the super class called?
By using the reference super(); When you invoke super(); the JVM knows that you are trying to invoke the constructor from the parent class and calls the super class constructor automatically. In fact, the invocation to super(); is usually the first line of any class constructor. This is done to ensure that all the parent class objects are initialized before the current child class is created.
How do you get viruses out of my PC?
download Malware-Bytes Anti-Malware and Avira Antivir or Super Anti Spyware
What is object class in java?
object class is a super class for all other class...
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; } }
