Subhadraa Exports Interview Questions and Answers

To get values present in table A but not in B without using joining conditions, minus, intersect, union, you can use a subquery.

• Use a subquery to select values from table A that are not present in table B

• Example: SELECT * FROM A WHERE value NOT IN (SELECT value FROM B)

Generate permutations and combinations of a given string without stored procedures.

• Use recursion to generate all possible permutations and combinations.

• Swap characters in the string to generate permutations.

• Use a boolean array to keep track of used characters in combinations.

• Store the generated permutations and combinations in an array of strings.

Questions related to Java programming language and memory management.

• Overriding is a concept where a subclass provides its own implementation of a method that is already present in its superclass.

• JVM stores class information in the method area and objects in the heap area.

• Serialization is the process of converting an object into a stream of bytes to store it in a file or send it over a network.

• Thread class methods include start(), run(), sleep(), join(), etc.

• StackOverflow exc...read more

Get 3 highest used words in a column from a table.

• Use GROUP BY and ORDER BY clauses in SQL query.

• Apply LIMIT 3 to get top 3 words.

• Use COUNT() function to count occurrences of each word.

Explains the working of hashmap and the difference between abstract class and interface.

• Hashmap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• Abstract classes are classes that cannot be instantiated and can have both abstract and non-abstract methods.

• Interfaces are contracts that define a set of methods that a class must implement.

• Using interfaces is better than abstract classes when multiple inheritance is needed or when a class ...read more

Reverse array in-place, find frequency of distinct elements, and implement Singleton class.

• To reverse an array in-place, swap the first and last elements, then move towards the center until the entire array is reversed.

• To find the frequency of distinct elements, use a hash table to count occurrences of each element.

• To implement a Singleton class, create a private constructor, a private static instance variable, and a public static method to return the instance.