Top 10 Courses to Crack System Design Interview in 2025 - Best of Lot

Hello guys, if you are preparing for System Design Interviews and looking for best resources then you have come to the right place. Earlier, I have shared best System design book, courses, websites, and System design interview questions and in this article, I am going to share in-depth System design courses from Educative.io, a text based online learning platform for developers and engineers. These are the best online courses to prepare for System Design Interviews in 2025.  If you have been doing Software development then you know that System design is one of the most important skill for developers and managers. 

4 Steps to Prepare for System Design Interviews in 2025? [The Ultimate Guide]

Hello guys, if you are preparing for Software Engineer Interviews, or Software developer interview then you may know that how difficult it is to prepare for them because of  System Design interviews, given its open ended nature and vastness but at the same time you cannot ignore it. In Software Engineering world, if you are applying for a Senior Engineer / Lead / Architect / or a more senior role, System Design is the most sought-after skill, and hence one of the most important rounds in the whole process. If you mess this up, nothing else would matter. If you get it right though, you’re looking at a raise of at least tens of thousands of dollars annually. 

How to System Design Trade Position Aggregator? [Solution]

Hello guys, it's been a long since I shared object-oriented design and system design questions in this blog. It was almost 7 to 8 years when I last blogged about how to solve vending machine design problems in Java and Twitter System Design question? Actually, I had ideas for lots of such design questions at that time, but because of the lengthy nature of these kinds of posts and the amount of time they take, they just sit on my list of drafts. I thought to take them out and publish then slowly improve on them instead of publishing the perfect post for the first time, and today, I am excited to share one of such problems, how to design a trade position aggregator in Java. This program is like portfolio management software that monitors your risk and exposure in real-time based on trades. 

Review - Is ByteByteGo System Design Interview Course by Alex Xu Really Worth it in 2025?

Hello guys, if you are preparing for System Design Interview in 2025 then you may have most likely come across names like ByteByteGo, Alex Xu or System Design Interview - An Insider Guide by Alex Xu, and if you are wondering what they are or you know about them but thinking whether ByteByteGo is worth it or not in 2025? then you have come to the right place. Yes, ByteByteGo is indeed worth considering for your System Design Interview preparation. because its created by Alex Xu, an expert with FAANG interview experience and platform offers in-depth coverage of system design topics. The author's use of diagrams to explain concepts in detail enhances the learning experience and most importantly Alex Xu regularly and new content and update old ones,.

How to Remove Duplicates from Array without Using Java Collection API? Example

This is a coding question recently asked to one of my readers in a Java Technical interview on investment bank. The question was to remove duplicates from an integer array without using any collection API classes like Set, HashSet, TreeSet or LinkedHashSet, which can make this task trivial. In general, if you need to do this for any project work, I suggest better using the Set interface, particularly LinkedHashSet, because that also keeps the order on which elements are inserted into Set. Why Set? because it doesn't allow duplicates and if you insert duplicate the add() method of Set interface will return false. 

How to find smallest number from int array in Java, Python, JavaScript and Golang? [Solved]

This is the second part on this array interview question. In the first part, I have showed you how to find the largest element in array, and in this part, you will learn how to find the smallest number from an integer array. We will solve this problem on Java programming language but you are free to solve in any other programming language like Python or JavaScript. Most interviewer doesn't care much about which programming language you are solving the question, if you can provide working solution. This one is also a popular Java programming exercise which is taught in school and colleges and give in homework to teach programming to kids and engineering graduates. 

How to Find Multiple Missing Integers in Given Array of Numbers with Duplicates in Java?

Hello guys, It's been a long time since I have discussed any coding or algorithm interview questions, so I thought to revisit one of the most popular array-based coding problems of finding missing numbers in a given array of integers. You might have heard or seen this problem before on your programming job interviews and you might already know how to solve this problem. But, there are a lot of different versions of this problem with increasing difficulty levels which interviewers normally use to confuse candidates and further test their ability to adapt to frequent changes, which is key to surviving in the ever-changing software development world.

Difference between a List and Array in Java? ArrayList vs Array Example

Hello there, if you are wondering what is the difference between a list and an array, or particularly an ArrayList and an Array in Java then you have come to the right place. Earlier, I have shared the best data structure and algorithm courses and in this article, I will explain to you the differences and similarities between a list and an array in Java.  Both array and ArrayList are two important data structures in Java and frequently used in Java programs. Even though ArrayList is internally backed by an array, knowing the difference between an array and an ArrayList in Java is critical for becoming a good Java developer. If you know the similarity and differences, you can judiciously decide when to use an array over an ArrayList or vice-versa. 

How to Find all Pairs in Array of Integers Whose sum is Equal to a Given Number in Java? Solution Example

Practicing coding problems are very important to do well in any programming interview. You should at your best on data structures like an array, linked list, and string to clear any programming interview and believe me, you can not do this in one day or one week. It's rather a long process of learning through coding, and that's where these small coding problems help. Today, we are going to look at another interesting programming question from the array; write a program to find all pairs of integers whose sum is equal to a given number. For example, if the input integer array is {2, 6, 3, 9, 11} and the given sum is 9, the output should be {6,3}.

How to Create and Initialize Anonymous Array in Java? Example

Anonymous arrays in Java is an Array without any name, just like Anonymous inner classes and policy of using Anonymous array is just create, initialize and use it, Since it doesn't have any name you can not reuse it. The anonymous array was a good way to implement variable argument methods before Java introduced varargs in Java5. You had the liberty to create an array of any length and pass that to a method that operates on an anonymous array. Classical example of such variable argument method is aggregate function like sum(), avg(), min(), max() etc.

Can You Make an Array or ArrayList Volatile in Java?

This is one of the many interesting multi-threading questions I have shared in my post 50 multi-threading interview questions. Yes, you can make an array volatile in Java, there is no problem with that, neither compiler will flag any error not JVM will throw any exception but the tricky part is why you want to make an array volatile and what is the effect of making an array volatile in Java? In order to answer this question, you must be familiar with both volatile modifier and Java memory model, otherwise, it would be difficult to answer, and that's why it's also one of the trick questions from Java interviews. Before answering this question in detail, let's first revise what is a volatile keyword in Java and what kind of guarantee it provides in the context of multithreading and concurrency.

Difference between Linked List and Array in Java? Example

Array and linked lists are two fundamental data structures in the programming world. Almost all programs use Array in some form or other, which makes it increasingly important to learn array and linked list. The difference between the linked list and array data structure is also a popular data structure question, frequently asked in the various programming job interviews. This makes it even more important to learn and understand the difference between an array and a linked list. Well, there are a lot of differences between these two starting from how they store data, to how you retrieve data from them.

How to merge two sorted arrays in Java? Example Tutorial

Hello guys, if you want to learn how to merge two sorted arrays in Java then you have come to the right place. Earlier, I have shown you how to sort arrays in Java, and in this article, I will show you how to merge two sorted arrays in Java. Btw, if you are a complete beginner then Firstly, you need to know what an array is before going about solving this problem about sorted array.  An array is a data structure in Java that holds values of the same type with its length specified right from creation time. This means you can create an integer array like int[] to store integer value. Think of a container, like a crate of eggs or coke, where number of places are fixed and you cannot change once you created it.

How to check if a given linked list is a palindrome in Java? Example [Solved]

Hello guys, if you are wondering how to check if a given linked list is a palindrome in Java then you have come to the right place. In the past, I have shared how to check if a given String is palindrome or a given number is a palindrome, and in this article, I will teach you how to check if a linked list is a palindrome. But before that, let's revise what is a palindrome? A palindrome is a phrase, word or number, or other sequence of characters that reads the same backward ad forward. Meaning that It gives you the same thing when read forward or backward. For example, Mary, Army, Madam, racecar, 1-2-3-2-1, noon, level, Hannah, civic, etc.

[Solved] How to reverse a Stack in Java using Recursion and Iteration? Example Tutorial

Hello guys, if you are wondering how to reveres a stack in Java then don't go anywhere. In this article, I will show you step by step how to reverse a given stack in Java. There are two ways to reverse a stack, you can use iteration or recursion. The most common way of reversing a stack is to use an auxiliary stack. First, we will pop all the elements from the stack and push them into the auxiliary stack. Once all the elements are pushed into the auxiliary stack, then it contains the elements in the reverse order and we simply print them. But, here, we will not use the auxiliary stack. We will use a recursion method to reverse a stack where recursion means calling the function itself again and again.