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Ans. Normalization is the process of splitting one Table into multiple so as to avoid Data duplication whereas Denormalization is the process of reducing Tables that creates data duplication but would remove joins in the queries.
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Ans. Relational Database uses linear search if we don't query using indices. Performance for linear search is O(n). If indices have been used , relational database uses binary search. Performance for binary search is O(Log n).
Casandra uses hash search. Performance for Hash Search is O(1).
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Ans. Any function call is slower than the code in the same method as Java has to maintain stack of meta and function call information. So recursion is slower.
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Ans. Because String being an immutable object creates a new object upon each concatenation cycle. If there is any such need , we should use String Builder whose objects are mutable.
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Ans. Because it doesn't make the change in the existing string but would create a new string by concatenating the new string to previous string. So Original string won't get changed but a new string will be created. That is why when we say
str1.concat("Hello");
It means nothing because we haven't specified the reference to the new string and we have no way to access the new concatenated string. Accessing str1 with the above code will still give the original string.
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Ans. ORM is the mapping technique, which maps object with relational data model. As we know that in java we need objects we can not user data in relational(in table form). So ORM is set of guideline which allows us to map relational data model in object form.
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Batching requires less resources but may result in loosing whole batch in case of failure whereas concurrency even though is little more expensive in terms of resources but would result in minimal loss in case of failure.
In case messages are to be consumed in a particular order, batching them in that order and then consuming them makes better sense.
if incoming messages are not continuous , it makes more sense to do concurrency as we need not wait for all messages to form a batch and flush. Though time sensitivity can be added but that would add unnecessary complexity.
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Ans. return is used within a method to return control out of the method. It may be followed by a value which is returned from the method to calling method immediately preceding the point of call.
break statement is used within a loop to move control out of the loop.
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Ans. return is used within a method to return control out of the method. It may be followed by a value which is returned from the method to calling method immediately preceding the point of call.
continue statement is used within a loop to start next iteration without executing the remaining statements in the loop.
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