Leadec India Interview Questions and Answers

ConcurrentHashMap is preferred for thread-safe operations, while HashMap and Hashtable are not.

• HashMap is not thread-safe and should not be used in a multi-threaded environment.

• Hashtable is thread-safe but has poor performance due to its synchronized nature.

• ConcurrentHashMap is thread-safe and has better performance than Hashtable due to its lock-free approach.

• Use ConcurrentHashMap when multiple threads are accessing the map concurrently.

• Use HashMap when only a single thread ...read more

This code reverses the characters of a string while keeping the order of words intact in C++.

• Split the string into words using a space as a delimiter.

• Reverse the entire string to get the characters in reverse order.

• Reverse each individual word to restore their original order.

• Example: Input: 'Hello World' -> Output: 'dlroW olleH'

Deep copy creates a new object with copies of nested objects; shallow copy copies references to nested objects.

• Shallow Copy: Copies the object's reference, not the actual object. Example: `list2 = list1.copy()`.

• Deep Copy: Creates a new object and recursively copies all objects found in the original. Example: `import copy; list2 = copy.deepcopy(list1)`.

• Shallow Copy is faster but can lead to unintended side effects if the original object is modified.

• Deep Copy is slower but ensu...read more

Use a SQL query to filter records where age is greater than 2.

• Basic SQL syntax: SELECT column_name FROM table_name WHERE condition;

• Example query: SELECT * FROM users WHERE age > 2;

• This query retrieves all records from the 'users' table where the age column has values greater than 2.

• Ensure the 'age' column is of a numeric type to avoid errors.

The Java Virtual Machine (JVM) calls the main method in Java.

• The main method is the entry point of a Java program.

• It is declared as public static void main(String[] args)

• The JVM searches for the main method in the class specified in the command line arguments.

• If the main method is not found, the JVM throws a NoSuchMethodError.

To create a REST API, define endpoints and HTTP methods. To create a REST client, use a library or make HTTP requests.

• Define endpoints and HTTP methods for the API

• Implement the API using a framework or library

• Test the API using tools like Postman

• To create a REST client, use a library like Retrofit or make HTTP requests using a library like OkHttp

• Parse the response from the API using a library like Gson

Developed a web-based project management system for a construction company.

• Used PHP and MySQL for backend development.

• Implemented a responsive UI using Bootstrap and jQuery.

• Incorporated features such as task assignment, progress tracking, and document management.

• Conducted user testing and made improvements based on feedback.

• Completed the project within the given timeline and budget.

To make a string palindrome, reverse the string and append it to the original string.

• Reverse the input string

• Append the reversed string to the original string