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Ans. Yes, compiler won't complain but at runtime it will give an error saying "Error: Main method not found in class". Even though we can use this method as any other private method, it cannot be invocate by executing the class. | ||||
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Ans. Default methods results in multiple inheritance of behavior and not of state. In case we try to implement multiple interfaces with default method having same name and signature, and don't override it in implementation class, it will throw an error. For example - interface MyInterface { public void default myMethod(){ } } interface MyInterface2 { public void default myMethod(){ } } class MyClass implements MyInterface,MyInterface2 { } This code will compilation error "Duplicate Default Method" if we specify the definition of myMethod() in myClass, compiler won't complain and there is no conflict and MyClass can use overridden definition. But if we don't override myMethod() in MyClass, Java would be in conflict as to what definition should be carried to MyClass and hence throws compilation error. | ||||
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Like Discuss Correct / Improve  default methods  java 8  multiple inheritance  object oriented programming (oops)  oops concepts  diamond problem   interfaces | ||||
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Ans. No, Main method is the entry point into an application. An application usually contain multiple classes to perform a function. Lets take an example of a House, House usually have only one external Door and you may have internal doors to move around within a house. Internal Doors are methods of classes whereas External Door is a special method called main method. | ||||
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Ans. Earlier any class implementing an interface was supposed to implement all methods declared in an interface. There was no place for optionally implementing all or subset of methods.Though we have abstract classes wherein we could have provided such a mechanism by declaring some methods as abstract while providing definition for some. But as Abstract classes have a body and are comparatively heavier than interfaces and interfaces associate closely to the concept of providing interfacing than abstract classes, Java might have though of providing optional implementation for default methods. This way same interface can be reused in variety of ways rather than making copies of an interface to suit different needs. | ||||
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Ans. Request Body in case of Get Request has no meaning and hence it's not parsed when the request is received. Alternatively Request Parameters are passed as either Path Params or Query Params. | ||||
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Ans. No. Static methods cannot be overridden and hence make no sense to be declared abstract. | ||||
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Ans. Yes, But the method should have some return type as otherwise it will be treated as a constructor. | ||||
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Ans. All methods defined in a class that are not marked static are actually instance methods. | ||||
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Ans. Though Static methods cannot access the instance variables directly, They can access them using instance handler. | ||||
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Like Discuss Correct / Improve  static   static method   java   oop   variables Asked in 1 Companies basic   frequent | ||||
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Ans. Its a method which cannot be overridden. Compiler throws an error if we try to override a method which has been declared final in the parent class. | ||||
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Like Discuss Correct / Improve  java   oops   final   final method Asked in 30 Companies basic   frequent | ||||
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Ans. No. Static methods belong to the class and not the objects. They belong to the class and hence doesn't fit properly for the polymorphic behavior. | ||||
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Ans. By putting code within static method. With Java 6 and earlier versions, even static block can be used. | ||||
Sample Code for static block | ||||
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Ans. A Method that cannot be overriden in the sub class. | ||||
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Ans. No. Static methods belong to the class and not the objects. They belong to the class and hence doesn't fit properly for the polymorphic behavior. A static method is not associated with any instance of a class so the concept of overriding for runtime polymorphism using static methods is not applicable. | ||||
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Like Discuss Correct / Improve  java   oops   static   static methods   java keywords   yes-no intermediate   frequent | ||||
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Ans. Yes.we cannot access them directly but we can access them using object reference.Static methods belong to a class and not objects whereas non static members are tied to an instance. Accessing instance variables without the instance handler would mean an ambiguity regarding which instance the method is referring to and hence its prohibited. | ||||
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Ans. We can do so through a static public member method or static block. | ||||
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Ans. You can create a non-static local class inside a body of code. Interfaces cannot have local classes, and you cannot create local interfaces. Local classes are accessible only from the body of the code in which the class is defined. The local classes are completely inaccessible outside the body of the code in which the class is defined. You can extend a class or implement interfaces while defining a local class. A local class can access all the variables available in the body of the code in which it is defined. You can pass only final variables to a local inner class. | ||||
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Ans. Both belong to the class as a whole and not to the individual objects. Static methods are explicitly called for execution whereas Static block gets executed when the Class gets loaded by the JVM. | ||||
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Ans. Program throws "NoSuchMethodError" error at runtime . | ||||
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Like Discuss Correct / Improve  java   main method   main   static   static method   nosuchmethoderror | ||||
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Ans. intern() method keeps the string in an internal cache that is usually not garbage collected. Moreover provide reference for scp object for corresponding string object present in heap memory. | ||||
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Like Discuss Correct / Improve  java   string class   string   intern method   garbage collection   advanced Asked in 2 Companies expert | ||||
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Ans. Yes. static method is not accessed by the instance of class. Either you call it by the class name or the reference. | ||||
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Ans. BuggyBread | ||||
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Ans. Buggy | ||||
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Ans. Buggy | ||||
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Ans. Compile Time Error: Unhandled exception type Exception | ||||
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Ans. Yes, but the overloaded main methods without single String[] argument doesn't get any special status by the JVM. They are just another methods that needs to be called explicitly. | ||||
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Like Discuss Correct / Improve  java   main method   overloading   yes-no Asked in 6 Companies intermediate   frequent | ||||
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Ans. Base Class Definition. | ||||
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Like Discuss Correct / Improve  java   java8   default methods | ||||
Rarely asked as default methods have been introduced with Java 8. | ||||
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Ans. No. Compiler will give error. | ||||
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Ans. No. Compilation error. | ||||
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Like Discuss Correct / Improve  java   java8   default method   yes-no Asked in 1 Companies intermediate | ||||
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Ans. With Java 8, We can provide method definitions in the Interfaces that gets carried down the classes implementing that interface in case they are not overridden by the Class. Keyword "default" is used to mark the default method. | ||||
Sample Code for interface default | ||||
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Like Discuss Correct / Improve  java   java8   default methods Asked in 7 Companies expert   frequent | ||||