Difference Between Comparator and Comparable. What is fully qualified domain name? What is the working principle for an ArrayList? How do you handle an exception? What is custom exception? What is the difference between checked and unchecked exception? If you close the database connectivity in try block and finally block as well then what is going to happen? Difference between abstract class and Interface.

Question

Accepted Answer

Comparator is used to compare objects for sorting, while Comparable is implemented by objects to define their natural ordering.

Comparator is an external class, while Comparable is implemented by the object itself.
Comparator can compare objects of different classes, while Comparable can only compare objects of the same class.
Comparator uses the compare() method, while Comparable uses the compareTo() method.

Accepted Answer

Comparator is a single sorting sequence like I'd name.

It affect the original

It is present in Java .lang

Comparable in words only having parable means more .comparable is a multiple sorting sequence. Like more I'd s more namee.

In election time these process is used.

Comparable present in Java util.

These domain are public string public string author they are eight domains . I wirte only two.

2) array list means to store elements. Array list are to remove and add.

3) catch block is used to handle exception

4) it is not a Java but it can store additional information like error code and provide utility method.

5) checked is complie time ,checked,handle at a time.

b) unchecked is runtime , non checked ,handle at atime but mistake is they .

6) any exception is not raised then no problem when exception raised the final block will be default..

7)

Abstract class only one class

Class A extendsB {

}

Interface means multiple class

Class A implements C,D,E{

}

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