Java 8 Stream API practice problems for beginners

After covering the Easy Level Java 8 Stream API practice, let’s move to the Hard Level — the type of problems you’ll often see in real interviews. Here are some advanced Stream API challenges I’ve solved: ✅ Find top 3 highest paid employees ✅ Group employees by department and find average salary ✅ Partition numbers into prime and non-prime ✅ Find the most frequent word in a list ✅ Find the second highest number ✅ Build a custom collector ✅ Find the longest palindrome word ✅ Flatten a JSON-like structure ✅ Sum transaction amounts by stock ✅ Find the kth smallest element ✅ Find the first non-repeating character 👉 I’ve shared the complete solutions in my GitHub repo: https://lnkd.in/dYQD2SVw This is Part 2 (Hard Level) in my Stream API series. If you missed the Easy Level (Part 1), you can check it out in my previous post. #Java #Java8 #JavaStreams #CodingChallenge #ProblemSolving

“Java 8 Stream API — Advanced Level Interview Questions ⚡ (Part 3)” After sharing Easy Level (Part 1) and Hard Level (Part 2) practice sets, here’s the Advanced Level (Part 3). These problems are tricky, but they help strengthen your mastery of Stream API for real-world use cases and interviews. Here are some challenges included: ✅ Find employees with duplicate names ✅ Find top-K frequent elements in a list ✅ Find common elements in two lists ✅ Check if two strings are anagrams ✅ Find the majority element in a list ✅ Find the first repeated character in a string ✅ Find the longest word in a sentence ✅ Find all numbers that appear exactly twice ✅ Find the kth largest element ✅ Find duplicate characters in a string 👉 Full practice code is available in my GitHub repo: https://lnkd.in/dnaD6GRT This is Part 3 of my Java 8 Stream API Series: Part 1: Easy Level Part 2: Hard Level Part 3: Advanced Level 🚀 #Java #Java8 #JavaStreams #CodingChallenge #ProblemSolving

Using streams with `java.time` makes generating, transforming, and querying a sequence of dates or times surprisingly concise, such as using `LocalDate.EPOCH.datesUntil(LocalDate.now()).map(...)`.

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Comparable (java.lang.Comparable) • Used to define the natural/default ordering of a class. • Class itself implements Comparable and overrides compareTo(Object o). • Affects how objects are sorted when using collections like TreeSet or Collections.sort(). • Limitation: Only one natural ordering per class. Comparator (java.util.Comparator) • Used to define custom ordering outside the class. • Implemented in a separate class (or using lambda/anonymous class). • Useful when you want multiple different sorting orders. • Provides compare(Object o1, Object o2) method.

Recently, I was troubleshooting a Java application(Servlet) where a few SQL queries were taking unusually long to execute. At first, it looked like a database issue — but digging deeper, I noticed something interesting 👀 During those heavy query executions, the JVM memory usage was spiking, and GC (Garbage Collection) was running frequently, slowing things down even more. After some profiling and monitoring, we realized that the default heap settings were too low for our workload. So we adjusted our system configuration The result? ✅ SQL executions became much more stable ✅ Noticeable improvement in overall performance This reminded me how small JVM-level configurations can make a big difference — especially in data-heavy services. Performance tuning isn’t just about optimizing code or queries; sometimes, it’s about understanding how your application and JVM handle memory under load.   #SpringBoot #Java #PerformanceTuning #BackendDevelopment #MemoryManagement

🔥 Day 80 of my 100 Days of Code Problem: Remove Linked List Elements (LeetCode #203) Problem Statement (Simplified): Remove all nodes of a linked list that have a given value. Code : class Solution { public ListNode removeElements(ListNode head, int val) { ListNode dummy = new ListNode(0); // Dummy node dummy.next = head; ListNode current = dummy; while (current.next != null) { if (current.next.val == val) { current.next = current.next.next; // Skip the node } else { current = current.next; // Move forward } } return dummy.next; } } Time Complexity: O(n) traverse the list once. Space Complexity: O(1) constant extra space (just dummy node). #Day80 #LeetCode #100DaysOfCode #Java

Exciting Project: Building & Deploying a Java Web Calculator Application Using Two Servers! I recently worked on an exciting project where I built and deployed a Java Web Calculator with a two-server architecture. The aim was to separate the build and deployment processes for better scalability and efficiency. Here’s how I tackled the entire setup: 🛠️ Project Breakdown: Server 1 (Build Server): Dedicated to compiling and packaging the application. Server 2 (Deploy Server): Handles deployment and serves the application to users. 🚧 Challenges Faced: Server Configuration: Setting up two Ubuntu servers with all the necessary dependencies (Java, Maven, Tomcat) was challenging but essential. Deployment Automation: I used scp to securely transfer the WAR file between servers, ensuring smooth deployment. Versioning & Compatibility: Ensuring the correct setup for both Java and Maven on both servers to avoid build or deployment issues. Managing Tomcat Setup: Installing and configuring Apache Tomcat on the deploy server was key to serving the web app properly. 💡 Key Takeaways: Separation of Concerns: Keeping build and deployment on separate servers made the process more organized and manageable. Automation: Automating the build and deployment with tools like Maven and scp helped streamline the process. https://lnkd.in/gMxhW-Cd: Java Web Calculator Build Documentation This was a fantastic learning experience where I enhanced my skills in deployment pipelines, server configuration, and troubleshooting. Looking forward to more challenging projects ahead! 💻 #Java #WebDevelopment #Maven #Tomcat #DevOps #Deployment #CI_CD #JavaDeveloper #CloudComputing #TechProjects

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