50 Java Interview Questions for SDET Automation Engineer

What is idempotent operation? What methods should be made idempotent?

What are common HTTP methods in REST you have used?

HTTP Status Codes 1.x to 5.x Explain the differences

How will you make REST automation framework? API automation

What is the difference between JDK JVM and JRE

What is super class in Java?

What is Polymorphism? What is Abstraction, give a practical example.

How will you make sure that main thread is the last one to exit?

Main Interfaces in Collections API - List, Set, Map. What is the difference between them?

Enumerator vs Iterator? Which one is thread safe?

Can collection classes be made serializable. How to do that?

Catch NPE first and Exception in last, will that work? Discuss the exception hierarchy. What are the inheritance rules for Exceptions?

Error and exception difference with an example. StackoverflowError, OOMError, etc.

Custom exceptions, how will you create one?

How will you compare two java objects?

Multiple inheritance in Java? How does Java 8 address this?

What is method overloading in Java?

What is method overriding in Java?

Difference between Overriding and Overloading a method

Inheritance vs Composition in Java

How to swap two numbers without a temporary variable? Discuss XOR approach. what are problems with addition approach?

Which one is better - extending Thread class or implementing Runnable interface

Check if the given sentence is Pangram or not

Calculate Fibonacci series in Java using recursion and iterative approach

How to reverse a number using Java

Check if the given number is a palindrome or not

Write a program to check if the given number is Armstrong number in Java

Write a program to reverse a string using recursion in Java

Write a Java program to check if two strings are anagrams

Searching an element from a sorted and rotated array.

Find two numbers of which the product is maximum in an array.

Reverse the ordering of words in a string

Check if a given number is Prime or not

Check whether given number is even or odd

What are different sorting algorithms

How to find the relative efficiency of a given algorithms

Find first not-repeating character by iterating through the length of the string only once and by using constant space.

Print prime numbers up to x

Implement a stack data structure.

JUNIT vs TestNG what are differences? Which one is better for QA?

TestNG hierarchy - Tests, suites, classes, etc.

Parameterization of tests in TestNG and data providers.

TestNG Listeners. How can these listeners be helpful.

Selenium and Rest API testing frameworks

How will you design API Testing suite

SDET - Rest Assured Interview Questions

SDET - JUnit interview questions for automation engineer

Basic shell commands and scripting

How to create a service for running jar

How to run a process in the background

How to make sure that a program is restarted if terminated

How to list selected processes

How to kill a process

How to search for keywords in files in current directory

What is awk command, sed command

How to copy a file from one machine to another?

How will you enable password less SSH login into server machine?

Continuously monitor last 100 lines of a log file.

How to connect to a remote server and execute certain commands.

I want to read all input to the command from file1 direct all output to file2 and error to file 3, how can I achieve this? unix pipes.

Unix permissions concepts chmod +x file.

How does password less login works? At a higher level.

How to find size of current directory?

How to check free disc space and memory in Unix?

How to list all running processes and see their cpu utilization?

How to find a process running on given port in mac/ubuntu

How to search given directory for specific text

How to find a given process in Unix and kill it

How to start a process in background mode, so that it keeps running even after terminal is closed.

What are different UNIX file permissions?

How to create a alias for a command in unix

How to setup public key authentication (passwordless login) on unix using ssh?

How to count lines and words in a text file.

How to get my IP address in unix

How a regular user can execute a command as an administrator

Employee and Department table - all employees from employee table and only departments that exists for an employee from department table. Left outer join.

How to delete duplicate records from a given table. (duplicate based on specified fields)

2nd highest salary in SQL, how will you find it out.

What is Inner Join and Left Outer Join

Find all those customers who have not placed any order yet. There are two tables Customer and Order, Order table contains foreign key to Customer table.

Maven and Gradle basics (PMD rules, Firebug, Code coverage tools, etc.)

What is CI and CD

How is your CI/CD and build environment setup in your project. Jenkins, Regression Test, etc. explain the stuff.

How to setup a build pipeline in jenkins

How to seamlessly deploy to AWS ec2 cloud upon single commit in version control. Just the high-level steps/approach.

How will you test APIs from security aspects. What are different areas you will cover?

What is vulnerability, exploit and threat?

What are top vulnerabilities in a web application?

Which guidelines will you follow for security testing a web application?