Core Java - Interview Questions and Answers for 'Enumerations' | Search Interview Question

Core Java - Interview Questions and Answers for 'Enumerations' - 5 question(s) found - Order By Newest

Q1. Can we override compareTo method for Enumerations ?

Ans. No. compareTo method is declared final for the Enumerations and hence cannot be overriden. This has been intentionally done so that one cannot temper with the sorting order on the Enumeration which is the order in which Enum constants are declared.

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Q2. What is an enumeration?

Core Java

Ans. An enumeration is an interface containing methods for accessing the underlying data structure from which the enumeration is obtained. It allows sequential access to all the elements stored in the collection.

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Q3. Shall we keep the enumeration name in all capital letters as it contains all constants ?

Ans. Enum is actually a class with pre defined constants. So enum name should follow the convention of the Class name. Though the constant names or the Enum variables should follow the convention of having all capital letters.

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Q4. In Hibernate, While defining Criteria, Have you ever faced any problem while adding restrictions with user defined types or Enums ?

Hibernate

Ans. Yes, with Enum as was getting an exception while doing equality check for enum field.

got it fixed by adding @Enumerated(EnumType.STRING) to the field in entity.

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Q5. What is the difference between Enumeration and Iterator ?

Core Java

Ans. Enumeration can iterate only legacy collections like Vector , HashTable and Stack whereas Iterator can iterate both legacy and non legacy collections.

Enumeration is less safer than Iterator

Enumeration is fail safe whereas Iterator is fail fast

Iterator allows for removal of element while traversal whereas Enumeration doesn't have remove method.

Enumerations were introduced in Java 1 whereas Iterators were introduced with Java 2

Enumerations have methods like hasMoreElements and nextElement whereas Iterators have methods like hasNext, next and remove

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