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Ans. By putting it within finally. | ||||
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Ans. Used to access members of the base class. | ||||
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Ans. Used to represent an instance of the class in which it appears. | ||||
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Ans. boolean is a primitive type whereas Boolean is a class. | ||||
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Ans. Serialization is the process of writing the state of an object to a byte stream. Deserialization is the process of restoring these objects. | ||||
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Ans. Inner class is a type of nested class. Inner classes are non static nested classes i.e the one that are associated with the instance of outer class. | ||||
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Ans. Any interface declared inside a class or an interface. It is static by default. | ||||
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Ans. Externalizable interface is used to write the state of an object into a byte stream in compressed format. | ||||
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Ans. Serializable is a marker interface whereas externalizable is not. | ||||
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Ans. Yes, as protected constructor is accessible in sub class. | ||||
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Ans. No Abstract methods can only be declared protected or public. | ||||
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Ans. Keep it as a Abstract Class if its a "Is a" Relationsship and should do subset/all of the functionality. Keep it as Interface if its a "Should Do" relationship. | ||||
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Ans. Yes. | ||||
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Ans. No. | ||||
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Ans. Combine the data of our application and its manipulation at one place. Encapsulation Allow the state of an object to be accessed and modified through behaviors. Reduce the coupling of modules and increase the cohesion inside them. | ||||
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Ans. new operator is used to statically create an instance of object. newInstance() is used to create an object dynamically ( like if the class name needs to be picked from configuration file ). If you know what class needs to be initialized , new is the optimized way of instantiating Class. | ||||
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Ans. 1. It shouldn't result in infinite loop. Please make sure that you have a condition that will terminate the loop and that condition should be reached. 2. Make sure to use the break statement if you aspire to only look for something. Not using break will unnecessarily execute it till the end of for loop in some cases. 3. Similarly use continue to execute the loop with next iteration and bypass the rest of the code block if required. 4. Try to avoid multiple nesting of for loops. If it''s required, Make sure to use break and continue properly so as to avoid some unnecessary processing. 5. Make sure to use try catch within the loop and not outside the for loop if you expect it to continue if one of the iteration fails. | ||||
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Ans. Abstraction is provided in Java by following ways - Coding to the ( Interfaces / Abstract Classes ) or contracts By Encapsulating details within classes and exposing the minimal Door ( few public methods ) | ||||
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Ans. Constructors , Classes ( Outer ) , Interfaces , Local variables , Inner Class methods and instance variables. | ||||
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Ans. Static Final Variables and Instance Method Declarations. | ||||
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Ans. Yes, we can do that. Compiler wont complain. But using object reference we can only access methods which have been defined for object class i.e clone(), equals(), hashCode(), toString() etc. We cannot access methods defined in String class or in any class in hierarchy between String and Object. For example - we cannot do obj.append("abc") as it will now give compile time error. | ||||
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Like Discuss Correct / Improve  object initialization  object declaration   runtime polymorphism  object oriented programming (oops)  oops concepts | ||||
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Ans. 1. for loop in java is used with a counter as following for(int counter=0;counter < 50;counter++){ System.out.println(list.get(counter)); } for iterating and printing the contents of a collection whereas foreach loop can be specified directly without the use of counter for(String str:list){ System.out.println(list.get(counter)); } 2. for Each loop syntax is more clean if we have to iterate over the elements of a collection and we need not keep track of the record count 3. For is preferred when we need loops without the usage of collections or Array of objects and entirely primitives are being used 4. for loop is preferred if we need to keep track of record count and have to perform some action of the basis of that. For example - If we have to print something after every 5 records, With for each loop in such case, we will have to keep a separate counter. | ||||
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Ans. Java identifies the method to be called at runtime by the object that is being referenced. | ||||
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Ans. Abstraction is a process of hiding the implementation details and describing only the functionality to the user. | ||||
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Ans. No | ||||
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Ans. Yes, to a certain extent. But the objective for Final class could be beyond just enforcing composition as certain classes might have been created without inheritance or composition in mind. | ||||
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Ans. 1. Enforcing composition over inheritance 2. Restricting overriding of certain methods 3. Final methods are faster than regular instance methods 4. Enforcing Immutability | ||||
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Ans. Cyclic instantiation in OOPs may happen if Class A loading results in Class B Loading , and then Class B Loading results in Class C loading and then Class C has a static reference to Class A and hence results in cyclic instantiation or loading. | ||||
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Ans. What if the initialization throws an exception. In that case , it will let it move forward without initializing the final field. So it's a way to enforce that either the field is initialized or it fails completely. | ||||
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Ans. No | ||||
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