Johnson Controls Lead Engineer Interview Questions and Answers

Strings are immutable because their values cannot be changed once they are created.

• Immutable objects cannot be modified once they are created

• String objects are created with a fixed value and cannot be changed

• Any operation that appears to modify a string actually creates a new string object

I have a strong skill set in programming languages such as Java, Python, and C++, with over 5 years of experience in each.

• Java - 7 years of experience, used in developing enterprise applications

• Python - 5 years of experience, used for data analysis and automation scripts

• C++ - 6 years of experience, used in embedded systems programming

The project is a web-based application for managing inventory and sales for a retail company.

• Developed using Java Spring framework

• Utilizes MySQL database for storing data

• Includes features such as user authentication, product management, and sales tracking

Use SQL query with ROW_NUMBER() function to delete duplicates and keep one.

• Use ROW_NUMBER() function to assign a unique number to each row partitioned by the duplicate column(s)

• Delete rows where the row number is greater than 1

Use Java Stream API to sort a list of employee objects based on a specific field.

• Use the sorted() method of Stream to sort the employee objects based on a Comparator.

• Define a Comparator based on the field you want to sort by.

• Example: List sortedList = employeeList.stream().sorted(Comparator.comparing(Employee::getSalary)).collect(Collectors.toList());