Java 25: Understanding the Limitations of Class-less Source Files

🚀 Mastering Pagination in Java — Beyond the Basics Pagination isn’t just about splitting data into pages — it’s about performance, scalability, and user experience. When working with large datasets in Java, especially using Spring Data JPA or Hibernate, fetching everything at once can quickly hurt performance. A simple way to implement pagination is by using Spring’s Pageable interface. For example, you can create a PageRequest with the desired page number, size, and sort order — something like creating a page request for users sorted by creation date in descending order and passing it to your repository method to get only the required slice of data. This approach ensures you never load more records than necessary. However, for very large tables, offset-based pagination (using SQL LIMIT and OFFSET) becomes slower as the offset grows. In such cases, keyset pagination (also called the seek method) is much more efficient. Instead of skipping rows, it fetches records based on the last seen ID — for example, selecting users where the ID is greater than the last fetched one and limiting the results to your page size. This avoids scanning skipped rows and keeps queries fast even with millions of records. It’s also a good practice to decouple backend pagination from frontend requests. Don’t expose database offsets directly through your API. Instead, use DTOs or wrapper objects that clearly define pagination metadata like total pages, total elements, and current page. Finally, if your pagination queries frequently hit the same data, consider caching or precomputing results for even better performance. 💡 Pro tip: Always test your pagination strategy with realistic data volumes. What feels fast with 1,000 rows might be painfully slow with 10 million. How do you handle pagination in your Java projects — offset, keyset, or something more creative? 👇 #Java #SpringBoot #Pagination #BackendDevelopment #Performance #Coding

In #Java, a class can have a field of the Collection type. When we create a new object of the class, we need to take few extra steps to handle Collection fields in a safe manner. You may say, wait a minute, the elements of my Collection, are immutable objects! Because they are implemented as Java records, or whatever technique you use to implement an immutable class. That simplifies the problem, but doesn't completely eliminate it. And the problem here is that the collection itself may not be an immutable object, what means that other parts of the application can hold the same collection reference and accidentally modify the collection in a way that wasn't expected by our custom class. The solution to this is to create a new reference for the collection and do defensive copy for all the elements. If we are using immutable elements, that solves the second part, we don't need to defensively copy immutable objects because they can't change. Regarding the first part, the quickest solution would be to use 𝐋𝐢𝐬𝐭.𝐜𝐨𝐩𝐲𝐎𝐟() method that will create a new list reference. But if you read the method documentation, you will see that this method will create an unmodifiable list, which doesn't support NULL list elements. So to bulletproof the logic, it's better to first filter out all null elements, and only after that return a new collection instance. If you use Stream API and its toList() method, it will return an unmodifiable list. Below code uses Java record compact constructor to create a new collection reference when instantiating an object:

🚀 Java 8 → Java 17: The Most Practical Features Developers Use Every Day Java has evolved significantly over the years, but only a few features have a real impact on daily development. Here are the most important, real-world, high-productivity features from Java 8 to 17 that every backend developer should use. Java 8 Foundation of Modern Java Lambdas → Cleaner, expressive functional code Stream API → Filtering, mapping, sorting, grouping Optional → Avoid null pointer issues java.time API → Modern date/time handling CompletableFuture → Async programming made simpler Java 9 List.of(), Set.of(), Map.of() → Quick immutable collections JShell → Test code instantly Java 10 var keyword → Cleaner declarations, faster development Java 11 (LTS) HTTP Client API → HTTP/2, async support String enhancements → isBlank(), strip(), repeat(), lines() Java 13–15 Text Blocks → Easy multi-line JSON, SQL, HTML Pattern Matching (preview) → Cleaner instanceof checks Java 16–17 (Modern Java) Records → Perfect for DTOs and API models Sealed Classes → Controlled inheritance for domain modeling Pattern Matching (finalized) → Cleaner type patterns Improved GC (ZGC, Shenandoah) → Low-latency microservice performance 🔥 Top 7 Features Used DAILY (Most Practical) 1️⃣ Stream API 2️⃣ Lambdas 3️⃣ var keyword 4️⃣ List.of(), Map.of() 5️⃣ String new methods (Java 11) 6️⃣ Records 7️⃣ Text Blocks If you're writing Java Code, these are the features you should use every day. #Java #Java17 #JavaDeveloper #BackendDevelopment #Programming #SoftwareEngineering

🌱 Why Did the Spring Framework Come in ? ## Spring came into the picture to make Java development simpler, faster, and more efficient — by removing the complexity and heaviness of old Java EE frameworks. 🌿 Understanding inversion of control and dependency injection in Spring ## Inversion of control : “IoC (Inversion of Control) is a design principle where the responsibility of object creation and dependency management is shifted from the developer to a framework or container In Spring, this container is called the IoC Container, which creates, configures, and manages beans. The main IoC containers in Spring are BeanFactory and ApplicationContext, ApplicationContext being the most commonly used.” ## Dependency injection : Dependency Injection (DI) is a design pattern in which an object’s dependencies (Beans )are provided (injected) by an external source such as an IoC container Constructor based and setter based dependency Injection and field based 🚗 a. Constructor Injection @Component class Car { private Engine engine; @Autowired public Car(Engine engine) { this.engine = engine; } } 🔧 b. Setter Injection @Component class Car { private Engine engine; @Autowired public void setEngine(Engine engine) { this.engine = engine; } } ⚡ c. Field Injection @Component class Car { @Autowired private Engine engine; } } #SpringFramework #JavaDevelopment #InversionOfControl #DependencyInjection #SpringBoot #JavaProgramming #BackendDevelopment #IoCContainer #ApplicationContext #BeanFactory #CleanCode #TechLearning #CodeWithSpring #JavaDevelopers #SpringCore #LearnJava

🚀 Methods vs. Constructors: Unpacking Key Differences in Java 🚀 New to Java or looking for a quick refresher? Understanding the distinction between Methods and Constructors is fundamental! While both contain blocks of code, they serve very different purposes. Let's break it down with a simple comparison: Constructors: The Blueprint Initializers 🏗️ Purpose: Primarily used to initialize new objects. Think of them as setting up the initial state when an object is first created. Name: Must have the same name as the class itself. Return Type: No return type (not even void). Invocation: Called automatically when you use the new keyword to create an object. Example: new Employee(101, "Alice"); Methods: The Action Performers ⚙️ Purpose: Used to perform actions or operations on an object, or to retrieve information from it. Name: Can have any valid name (following Java naming conventions). Return Type: Must have a return type (e.g., void, int, String, Employee, etc.). Invocation: Called explicitly using the object reference, like object.methodName(). Example: employee.getDetails(); or employee.calculateBonus(); In essence: Constructors build and set up your object. Methods make your object do things. Understanding this distinction is crucial for writing clean, efficient, and object-oriented Java code! Thanks Anand Kumar Buddarapu #Java #Programming #SoftwareDevelopment #OOP #Constructors #Methods #CodingTips

🚀 Heads-up Java devs: the entry point just got a makeover If you thought every Java program had to start with public static void main(String[] args), the times are changing. With Java SE 21 and onward, the rules around the main() method have been relaxed. Medium+2 🔍 What’s new Java can now use instance main() methods (without static) or even main() with no parameters, in implicitly declared classes. You can skip writing the outer public class HelloWorld { … } in some contexts ("compact source files"). These features started as preview in Java 21 (JEP 445) and later became re-preview in Java 22 (JEP 463). 👍 Why this matters Less boilerplate: Faster to spin up a quick demo or script. Cleaner code: More readable, especially for newbies or quick utilities. Modernised Java: Aligns Java more with scripting or lightweight languages for rapid dev. 📣 Want to try it? // Java 21+ preview mode or above void main() { IO.println("Hello, world!"); } Yep — no public, no static, no args array. Though note: preview features may need enabling until finalised. 🗣 Let’s talk Have you experimented with this new main method style? Would you adopt it in production code, or is it just for demos & quick scripts? What’s a change in Java you wish would come next? Drop your thoughts below — and if you found this useful, hit Follow for more Java/Spring/tech-deep dives. #Java #Java21 #ProgrammingLanguages #SoftwareEngineering #DeveloperNews #SpringBoot #JobOpportunity

🚀 When Java’s HashMap Switches from Linked List to Balanced Tree — and Why It Matters! Did you know that Java’s HashMap got smarter since Java 8? 😎 When multiple keys land in the same hash bucket (due to hash collisions), older versions of Java stored them in a linked list — giving O(n) lookup time in the worst case. But Java 8+ said: “Let’s fix that!” 🔧 Here’s what happens now 👇 ✅ If a bucket gets 8 or more entries, it’s converted from a LinkedList to a Balanced Red-Black Tree. ✅ This makes lookups much faster — turning worst-case O(n) into O(log n). ✅ If the number of entries later drops below 6, it switches back to a linked list. ✅ Treeification only happens when the map capacity is at least 64 — otherwise, it just resizes. 💡 Performance insight: You’ll almost never notice this change in everyday use — because good hash distribution keeps buckets small. But it’s a great defensive design that keeps your application safe from performance drops or hash-collision attacks. 🔍 Pro tips for developers: Always implement a strong hashCode() for custom objects. Initialize maps with a sensible capacity if you know their expected size. Remember, this feature doesn’t replace good design — it’s just a safety net! 📊 In short: Java 8’s HashMap automatically switches to a red-black tree when collisions get heavy, improving lookup speed from O(n) → O(log n). #Java #SpringBoot #HashMap #Coding #Performance #Java8 #DeveloperTips #TechLearning

💡 Is the finally block losing its importance in modern Java? If you’ve been working with Java for a while, you’ve surely used the finally block — the trusty companion that ensures resources are released no matter what happens in your try block. Example 👇 FileInputStream fis = null; try { fis = new FileInputStream("data.txt"); // process file } catch (IOException e) { e.printStackTrace(); } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { e.printStackTrace(); } } } ✅ The intention was solid — guarantee cleanup, even when exceptions occur. ⚠️ But the problem? The finally block itself can throw exceptions or mask the original one. For example, if fis.close() fails, the real cause of the failure inside try might be lost. That’s why modern Java developers have largely moved away from finally for resource handling. 🚀 Enter try-with-resources (Java 7+) It automatically closes resources that implement AutoCloseable, making your code safer and cleaner. Example 👇 try (FileInputStream fis = new FileInputStream("data.txt")) { // process file safely } catch (IOException e) { e.printStackTrace(); } ✨ Benefits: No need for explicit finally cleanup. Prevents resource leaks. Preserves the original exception. More concise and readable code. So yes — the finally block still exists, but in most cases, it’s been gracefully replaced by try-with-resources, the safer and modern approach. #Java #CodingTips #Developers #CleanCode #JavaProgramming #ExceptionHandling #SoftwareEngineering

Spring Annotations — The Secret Sauce Behind Cleaner Java Code When I first started working with the Spring Framework, I remember being amazed by how a few words with an @ symbol could replace pages of configuration. That’s the beauty of annotations — they make Spring feel intuitive, elegant, and powerful. Here are some I keep coming back to: @Component / @Service / @Repository / @Controller Tell Spring, “Hey, manage this class for me!” — and just like that, it becomes a Spring bean. @Autowired Dependency injection made simple — no need for manual wiring; Spring handles it all behind the scenes. @Configuration & @Bean Say goodbye to XML configs. Define your beans right in code, clean and readable. @RestController & @RequestMapping Building REST APIs? These two make it a breeze to handle endpoints and responses. @Transactional Handles transactions automatically so you don’t have to worry about rollbacks or commits — magic for database operations. @SpringBootApplication The grand entry point — combines multiple annotations into one neat package and spins up your app in seconds. Every time I use these, I’m reminded how much Spring has evolved — from heavy XML setups to annotation-driven simplicity. What’s the one Spring annotation you can’t live without? #SpringBoot #JavaDevelopers #BackendDevelopment #SpringFramework #CodingLife #TechCommunity