JAVAPRO’s Post

Day 39 – Deep Dive into Java Strings ☕ Today I focused on revising and understanding Strings in Java in detail. Topics covered: 🔹 Types of Strings (String, StringBuilder, StringBuffer) 🔹 Immutable nature of Strings 🔹 Memory allocation (String Constant Pool vs Heap Area) 🔹 Different ways to compare Strings (==, equals(), equalsIgnoreCase(), compareTo()) 🔹 String concatenation using + vs concat() Understanding how strings are stored in memory and how comparisons work helped me gain deeper clarity on writing efficient and correct programs. #Day39 #JavaJourney #Strings #CoreJava #ProgrammingFundamentals #Consistency

💡 Strings in Java — Small Concept, Big Impact At first, I thought Strings were simple… But in real projects, I learned: ➡️ Strings are immutable ➡️ Memory is optimized using String Pool ➡️ Wrong usage can impact performance Example mistake I made: String result = ""; for (int i = 0; i < 1000; i++) { result += i; // ❌ creates multiple objects } ✅ Better approach: StringBuilder sb = new StringBuilder(); for (int i = 0; i < 1000; i++) { sb.append(i); } ✨ What I learned: ✔ Use StringBuilder for heavy operations ✔ Understand equals() vs == ✔ Be mindful of memory Sometimes the simplest concepts teach the biggest lessons. #Java #Strings #CleanCode #SoftwareEngineering #BackendDevelopment #LearningJourney

Java 21 Feature Spotlight: Switch Pattern Matching One of the most powerful improvements in Java 21 is switch pattern matching. It allows you to match object types and extract values directly inside a switch, removing the need for complex if-else blocks and manual casting. 👉 Example: Object obj = "Hello"; switch (obj) { case String s -> System.out.println(s.length()); case Integer i -> System.out.println(i * 2); default -> System.out.println("Unknown"); } ✅ Cleaner code ✅ No explicit casting ✅ Better readability ✅ Safer type handling This feature is especially useful in backend development when handling multiple request types, DTOs, or events. 💡 In simple terms: You write less code, and your logic becomes easier to understand and maintain. #Java #Java21 #BackendDevelopment #SpringBoot #Programming #SoftwareDevelopment

Day 59 — LeetCode Progress (Java) Problem: Count the Number of Consistent Strings Required: Given a string allowed and an array of strings words, return the number of consistent strings (strings that contain only characters from allowed). Idea: Use a HashSet for fast lookup to check whether each character in a word is allowed. Approach: Store all characters of allowed in a HashSet. Iterate through each word: Check every character in the word If any character is not in the set, the word is invalid Count all valid (consistent) words. Time Complexity: O(n × m) Space Complexity: O(1) #LeetCode #DSA #Java #HashSet #Strings #Algorithms #CodingJourney #100DaysOfCode

Day 51 – Understanding Static Concepts in Java ☕ Today I learned about static variables, static methods, and static blocks in Java. Topics covered: 🔹 Static variables and their shared nature across objects 🔹 Static methods and how they can be accessed without creating objects 🔹 Static blocks and their role in initialization Understanding how static members belong to the class rather than objects helped me gain better clarity on memory usage and execution flow in Java. Strengthening my understanding of Java internals step by step 🚀 #Day51 #JavaJourney #CoreJava #Static #JVM #Consistency

Day 24 of Java Backend Journey 💻🔥 Built a Logger System using File Handling in Java! ✔️ Stored user input into files ✔️ Implemented append mode ✔️ Displayed logs dynamically Understanding how real backend systems store data step by step 🚀 #Java #BackendDevelopment #100DaysOfCode #LearningInPublic

🤯 Yesterday I learned that ArrayList is dynamic… Today I explored how it actually grows internally in Java. Here’s the simple idea 👇 👉 ArrayList internally uses a normal array 👉 When the array becomes full, Java creates a new bigger array 👉 Old elements are copied into the new one 👉 Capacity usually increases by 1.5x Example: 10 → 15 → 22 → 33 This is what makes ArrayList flexible while still being fast. 💡 Key takeaway: ArrayList looks dynamic from outside, but internally it still depends on arrays + resizing logic. Small internal details like this make Java collections much more interesting. #Java #ArrayList #DSA #LearningInPublic

Just dropped a new video on Comparator Interface in Java — covering custom sorting logic using multiple approaches (class, anonymous class and lambda). A clean, visual explanation to make sorting truly click. #Java #Comparator #Coding #LearningEveryday Watch here: https://lnkd.in/geW_UKh9

Day 32/100 — Pattern Matching in Java 16+ 🎯 The old way was painful: if (obj instanceof String) {   String s = (String) obj; // explicit cast!   s.length(); } Java 16+ makes this clean: if (obj instanceof String s) {   s.length(); // no cast needed! } Java 21 switch pattern matching: String result = switch (obj) {   case Integer i -> "int: "  + i;   case String s -> "string: " + s;   case Double d -> "double: " + d;   default    -> "unknown"; }; Guarded patterns — add extra conditions: case String s when s.length() > 5 -> "long string!" 3 rules to remember: → Binding variable is already the correct type → Works with sealed classes — no default needed! → Compiler checks exhaustiveness automatically 🎯 Challenge: Write a method that takes Object and returns a description using switch pattern matching! #Java #PatternMatching #Java21 #CoreJava #100DaysOfJava #100DaysOfCode

Day 47: Huffman Encoding Problem: Generate Huffman codes for a set of characters with given frequencies. How It Works: Merge lowest frequency nodes to build a Huffman tree. If frequencies are equal, earlier characters are prioritized. Assign binary codes from the tree to each character. Single character gets code "0". #geekstreak60 #npci #Java