Pentagon Space Senior Technical Trainer Interview Questions and Answers

Multithreading can be created in programming by creating multiple threads within a single process to execute tasks concurrently.

• Use a programming language that supports multithreading, such as Java or C++.

• Create a new thread by extending the Thread class or implementing the Runnable interface.

• Start the thread using the start() method to execute the run() method concurrently.

• Handle synchronization and communication betw...read more

Customized exceptions can be created by extending the Exception class for checked exceptions and RuntimeException class for unchecked exceptions.

• Create a new class that extends Exception for checked exceptions or RuntimeException for unchecked exceptions

• Override the constructors to provide custom messages and error codes

• Throw the customized exception in your code when necessary

Java program to check if strings are anagrams

• Create a method that takes in two strings as parameters

• Convert both strings to char arrays and sort them

• Check if the sorted arrays are equal to determine if the strings are anagrams

Aggregate functions in MySQL are used to perform calculations on a set of values and return a single value.

• Aggregate functions include functions like SUM, AVG, COUNT, MIN, and MAX.

• They are often used with the GROUP BY clause to group the result set by one or more columns.

• Aggregate functions ignore NULL values unless specified otherwise.

• Examples: SELECT SUM(salary) FROM employees; SELECT AVG(age) FROM students;

Query to display details of employees whose names start with 'ab' in MySQL.

• Use SELECT statement to retrieve data from the table.

• Use WHERE clause with LIKE operator to filter names starting with 'ab'.

• Example: SELECT * FROM employees WHERE name LIKE 'ab%';

Yes, an example of immutable object other than strings in Java is the Integer class.

• Integer class in Java is immutable, meaning its value cannot be changed once it is created.

• When you perform operations on an Integer object, a new Integer object is created with the result.

• Example: Integer num = 10; num += 5; // num is now a new Integer object with value 15

Service annotation in Spring is used to indicate that a class is a Spring bean and should be managed by the Spring container.

• Service annotation is used to mark a class as a Spring bean

• It eliminates the need for XML configuration for bean definition

• It allows for automatic detection and registration of beans in the Spring container

• Example: @Service annotation on a class named UserService

Transitive dependency in MySQL refers to a condition where a non-key attribute depends on another non-key attribute.

• A transitive dependency occurs when A -> B and B -> C, leading to A -> C.

• Example: In a table with columns StudentID, CourseID, and Instructor, if Instructor depends on CourseID, it's a transitive dependency.

• Transitive dependencies can lead to data redundancy and anomalies in database design.

• To el...read more

Synchronization is necessary while creating a thread to ensure proper coordination and avoid conflicts between multiple threads accessing shared resources.

• Prevents data corruption: Synchronization helps in preventing data corruption when multiple threads access shared data simultaneously.

• Maintains order of execution: Synchronization ensures that threads execute in a specific order, preventing race conditions.

• Avoids dea...read more

Daemon thread runs in the background and does not prevent the JVM from exiting, while single thread is a regular thread that can prevent the JVM from exiting.

• Daemon thread is used for background tasks like garbage collection, while single thread is used for regular tasks.

• Daemon thread does not prevent the JVM from exiting, while single thread can prevent the JVM from exiting.

• Daemon threads are terminated by the JVM whe...read more

Agile methodologies in CRM involve iterative development, frequent feedback, and collaboration.

• Break down CRM projects into smaller tasks or user stories

• Hold regular sprint planning meetings to prioritize tasks and set goals

• Encourage cross-functional teams to work together and communicate effectively

• Use tools like Jira or Trello to track progress and manage tasks

• Conduct regular retrospectives to reflect on what went we...read more