Niveshan Technologies India Interview Questions and Answers

For loop is used for iterating over a range of values while for each loop is used for iterating over elements of an array.

• For loop is used when the number of iterations is known beforehand.

• For each loop is used when the number of iterations is not known beforehand.

• For loop can be used with any iterable object.

• For each loop can only be used with arrays and other iterable objects.

• For loop uses an index variable to access...read more

The HashMap class is used to represent key-value pairs in Java.

• HashMap is a part of the Java Collections Framework.

• It allows null values and only one null key.

• It provides constant-time performance for basic operations like get and put.

• Example: HashMap<String, Integer> map = new HashMap<>();

Abstraction is the process of simplifying complex systems by focusing on essential details and hiding unnecessary complexities.

• Abstraction allows us to create models or representations of real-world objects or systems in software.

• It helps in managing complexity by breaking down a system into smaller, more manageable parts.

• Abstraction provides a level of indirection, allowing changes to be made in one part of the system...read more

try-catch is used in Java to handle exceptions and prevent program crashes.

• try-catch blocks are used to catch and handle exceptions that may occur during program execution.

• It allows the program to gracefully handle errors and prevent the program from crashing.

• The try block contains the code that may throw an exception, and the catch block handles the exception.

• Multiple catch blocks can be used to handle different types...read more

The statement to use for selecting based on integer inputs is the 'switch' statement.

• The 'switch' statement allows for multiple cases to be evaluated based on the value of an integer input.

• Each case represents a possible value of the input, and the corresponding code block is executed if the value matches.

• The 'switch' statement also provides a 'default' case which is executed if none of the cases match the input value.

• ...read more

Joins in SQL are used to combine data from two or more tables based on a related column.

• Inner join returns only the matching rows from both tables

• Left join returns all rows from the left table and matching rows from the right table

• Right join returns all rows from the right table and matching rows from the left table

• Full outer join returns all rows from both tables, with NULL values for non-matching rows

• Cross join retur

Given an array of integers, find a contiguous subarray with a given sum.

• Use a sliding window approach to iterate through the array and keep track of the current sum.

• If the current sum exceeds the given sum, move the window's left endpoint forward.

• If the current sum is less than the given sum, move the window's right endpoint forward.

• If the current sum equals the given sum, return the subarray.

• Time complexity: O(n), Spa