60+ Senior Application Developer Interview Questions and Answers

I will use try-catch blocks to handle exceptions and log the error message for debugging purposes.

• Enclose the procedure call in a try block.

• Catch the exception in the catch block.

• Log the error message for debugging purposes.

• Handle the exception appropriately based on the specific scenario.

Use a routing library like React Router to manage navigation and organize components into separate pages.

• Utilize React Router to set up routes for each page and handle navigation

• Organize components into separate folders based on their functionality or page they belong to

• Consider lazy loading components to improve performance, especially with a large number of pages

When passing an object as the key in a map, extra functionality needs to be implemented to ensure proper hashing and equality comparison.

• Override hashCode() method to generate a unique hash code for the object

• Override equals() method to compare the objects for equality

• Implement Comparable interface if custom sorting is required

Functional interfaces can have only one abstract method, but can have multiple static and default methods.

• Functional interfaces in Java can have only one abstract method, but can have multiple static and default methods.

• Static methods in functional interfaces can be called using the interface name itself.

• Default methods provide a default implementation in the interface itself.

• Example: java.util.function.Function is a functional interface with one abstract method and default m...read more

Implemented a complex data migration from legacy system to new system

• Identified all data sources and mapped them to new system

• Developed custom scripts to transform and validate data

• Performed multiple test runs to ensure data integrity

• Coordinated with stakeholders to ensure smooth transition

There are three ways to communicate in LWC: event communication, public properties, and method calls.

• Event communication: Components can communicate by firing and handling events.

• Public properties: Components can communicate by passing data through public properties.

• Method calls: Components can communicate by calling methods on other components.

SQL query to retrieve top 10 salaries from employee table.

• Use SELECT statement to retrieve data from employee table

• Use ORDER BY clause to sort the data in descending order based on salary

• Use LIMIT clause to limit the result set to top 10 salaries

Use synchronization mechanisms like barriers or join to aggregate parallel threads

• Use synchronization mechanisms like barriers or join to wait for all threads to complete before proceeding

• Implement a barrier that blocks all threads until they all reach a certain point in the code

• Use a join operation to wait for all threads to finish before continuing execution

To swap the value of two variables without using a third variable, use arithmetic operations.

• Use addition and subtraction to swap values

• Example: a = 5, b = 10. a = a + b (a = 15), b = a - b (b = 5), a = a - b (a = 10)

JS works by interpreting and executing code line by line, hoisting moves variable declarations to the top, event loop manages asynchronous operations, Reactjs and Redux are popular libraries for building user interfaces.

• JS works by interpreting and executing code line by line.

• Hoisting in JS moves variable declarations to the top.

• Event Loop in JS manages asynchronous operations.

• Reactjs and Redux are popular libraries for building user interfaces.

There are two types of exceptions: checked and unchecked.

• Checked exceptions are checked at compile-time and must be handled by the programmer.

• Unchecked exceptions are not checked at compile-time and can be handled by the JVM.

• Examples of checked exceptions include IOException and SQLException.

• Examples of unchecked exceptions include NullPointerException and ArrayIndexOutOfBoundsException.

Use Comparator interface to sort objects by fields in Java.

• Implement Comparator interface and override compare method

• Use Collections.sort() method with custom Comparator

• Example: Sorting a list of Person objects by age field

Optimizing an application involves identifying and resolving performance bottlenecks to improve efficiency and user experience.

• Identify and address slow database queries or inefficient code

• Implement caching mechanisms to reduce load times

• Optimize images and assets to reduce file sizes

• Utilize asynchronous processing to improve responsiveness

• Profile and analyze code to identify areas for improvement

Inner join returns only the rows that have matching values in both tables, while left/right/full outer join returns all rows from one table and matching rows from the other table.

• Inner join: returns rows with matching values in 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 when there is a match in either ta...read more

Implementing Spring security involves configuring security settings in the Spring application.

• Add Spring Security dependency in pom.xml

• Configure security settings in SecurityConfig class

• Define user roles and permissions

• Use annotations like @EnableWebSecurity and @Secured

Software Development Life Cycle is a process followed by software developers to design, develop and maintain software.

• SDLC consists of several phases including planning, analysis, design, implementation, testing, deployment, and maintenance.

• Each phase has its own set of activities and deliverables.

• The goal of SDLC is to ensure that the software meets the requirements of the stakeholders and is delivered on time and within budget.

• SDLC models include Waterfall, Agile, and DevOp...read more

LinkedList and ArrayList are both implementations of the List interface in Java. LinkedList uses pointers to connect elements, while ArrayList uses a dynamic array to store elements.

• LinkedList uses pointers to connect elements, allowing for efficient insertion and deletion operations.

• ArrayList uses a dynamic array to store elements, providing fast random access to elements.

• LinkedList is better suited for frequent insertions and deletions, while ArrayList is better for frequen...read more

Design an ETL system for loading structured data

• Identify data sources and destinations

• Create data extraction processes

• Transform data to match destination schema

• Load transformed data into destination

Singleton pattern ensures a class has only one instance, while ConcurrentHashMap allows multiple threads to access and modify a map concurrently.

• Singleton pattern involves creating a class with a private constructor and a static method to return the instance.

• ConcurrentHashMap is a thread-safe implementation of the Map interface, allowing multiple threads to access and modify the map concurrently.

• To implement a singleton pattern, use a private static instance variable and a st...read more

In LWC, == is used for loose equality comparison while ==== is used for strict equality comparison.

• == is used for comparing values without considering data types

• === is used for comparing values while also considering data types

• Example: '1' == 1 will return true, but '1' === 1 will return false

Context API is a feature in React that allows sharing data between components without having to pass props through every level of the component tree.

• Context API provides a way to pass data through the component tree without having to pass props down manually at every level.

• It is particularly useful for passing down global data like themes, user authentication, or language preferences.

• Context API consists of three main parts: the Provider, the Consumer, and the useContext hook...read more

Test suite for a login form

• Test for valid username and password

• Test for invalid username and password

• Test for empty username or password field

• Test for special characters in username or password

• Test for maximum character limit in username and password fields

COND parameter is used in JCL to specify a condition for executing a job step.

• COND parameter is used in IF/THEN/ELSE statements to determine the execution of a job step.

• It can be used to check the return code of a previous step or a specific condition.

• COND parameter can have values like ONLY, EVEN, ONLY EVEN, etc.

• It can also be used with the NOT operator to negate the condition.

• COND parameter can be used with job steps, procedures, and in-stream data sets.