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| Core Java - Interview Questions and Answers for 'Inheritence' - 10 question(s) found - Order By Newest | |||||
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| Ans. 1. Overriding method can not be more restrictive than the overridden method. reason : in case of polymorphism , at object creation jvm look for actual runtime object. jvm does not look for reference type and while calling methods it look for overridden method. If by means subclass were allowed to change the access modifier on the overriding method, then suddenly at runtime when the JVM invokes the true objects version of the method rather than the reference types version then it will be problematic 2. In case of subclass and superclass define in different package, we can override only those method which have public or protected access. 3. We can not override any private method because private methods can not be inherited and if method can not be inherited then method can not be overridden. | |||||
 Sample Code for Overriding | |||||
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 Discuss Correct / Improve  java overriding access specifier inheritence oops polymorphism runtime polymorphism  Genpact | |||||
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| Ans. Derived object carries the body of its class as well as the body of the parent class. Its body ( member elements ) is initialized using its own class constructor whereas the body ( member elements ) carried from the parent class are initialized using super class constructor. So In order to initialize the elements of the parent class before its own elements are even initialized, super is called. | |||||
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Discuss Correct / Improve java oops constructor super inheritance inheritence Itech  intermediate | |||||
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| Ans. Java doesn't support multiple inheritance. Interfaces does't facilitate inheritance and hence implementation of multiple interfaces doesn't make multiple inheritance. | |||||
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Discuss Correct / Improve java oop oop concepts inheritence multiple inheritence basic interview question Credit Suisse Sun Microsystems VMware NSEiT Exterro theScore JP Morgan Computrade Israel basic  frequent | |||||
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| Ans. You cannot inherit a constructor. That is, you cannot create a instance of a subclass using a constructor of one of it's superclasses. One of the main reasons is because you probably don't want to override the superclasses constructor, which would be possible if they were inherited. By giving the developer the ability to override a superclasses constructor you would erode the encapsulation abilities of the language. | |||||
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| Discuss Correct / Improve java oops constructor inheritence expert rare | |||||
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| Ans. 1.this is a reference to the current object in which this keyword is used whereas super is a reference used to access members specific to the parent Class. 2.this is primarily used for accessing member variables if local variables have same name, for constructor chaining and for passing itself to some method whereas super is primarily used to initialize base class members within derived class constructor. | |||||
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| Discuss Correct / Improve java oops class objects inheritence constructor this super | |||||
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| Ans. 1)The overriding methods can throw any runtime Exception , here in the case of runtime exception overriding method (subclass method) should not worry about exception being thrown by superclass method. 2)If superclass method does not throw any exception then while overriding, the subclass method can not throw any new checked exception but it can throw any runtime exception 3) Different exceptions in java follow some hierarchy tree(inheritance). In this case , if superclass method throws any checked exception , then while overriding the method in subclass we can not throw any new checked exception or any checked exception which are higher in hierarchy than the exception thrown in superclass method | |||||
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| Discuss Correct / Improve java overriding exceptions inheritence inheritance oops | |||||
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| Discuss Correct / Improve java oops access specifier overriding overridding inheritence yes-no | |||||
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| Ans. co-variant return type states that return type of overriding method can be subtype of the return type declared in method of superclass. it has been introduced since jdk 1.5 | |||||
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| Discuss Correct / Improve java oops inheritence overriding covariant return type jdk5 advanced Hewlett Packard (HP) The Systems Group Evergent expert | |||||
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| Ans. class A { void test() { System.out.println("test() method"); } } class B { void test() { System.out.println("test() method"); } } Suppose if Java allows multiple inheritance like this, class C extends A, B { } A and B test() methods are inheriting to C class. So which test() method C class will take? As A & B class test() methods are different , So here we would Facing Ambiguity. | |||||
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| Discuss Correct / Improve java oops inheritence multiple inheritence Clover Infotech basic frequent | |||||
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