Java String Operations and Comparison Methods

Day 37 of Learning Java Today I learned something interesting Illegal Forward Reference in Java. At first, it sounded complicated, but once I understood it, it actually made a lot of sense! Here’s what I learned: 🔹 What is Illegal Forward Reference?   • It happens when you try to use a variable before it is declared.   • Java doesn’t allow referencing a variable that comes later in the code. 🔹 Why does it happen?   • Java reads code from top to bottom.   • If a variable is used before it exists, the compiler throws an error. 🔹 Example of the issue:   • Using a variable before declaring & defining it to a compile-time error. 🔹 How to fix it?   • Always declare variables before using them.   • we have to call static variable using ClassName.VarName. Thanks to my mentor Ashim Prem Mahto for the clear explanations and for always clearing my doubts. #Java #LearningJava #CodingJourney #Programming #DeveloperLife #CodeNewbie #JavaDeveloper #TechLearning #StudentLife #jvm

Day 39 of learning java Today I learned something very important in Java, Object Creation. Syntax: "className objectName = new constructor();" Here’s what I understood: • The left side ("className objectName") is just declaring a reference variable. • The right side ("new constructor()") is where the actual object is created. • Memory is allocated only when we use the "new" keyword. • The constructor gets executed automatically when the object is created. • Without "new", no memory is allocated and no constructor runs. In short: Declaration != Object creation You need "new" to actually create and use the object. This concept made things much clear about how Java handles memory and execution internally. Thanks to my mentor Ashim Prem Mahto for the clear explanations and for always clearing my doubts. #Java #LearningJourney #Programming #JavaBasics #CodingLife #DeveloperJourney #TechLearning #Beginners #CodeNewbie #jvm #SoftwareEngineer #StudentLife

#Day_13 of My Java Learning Journey – Writing Functions in Java Today I practiced how to create functions (methods) in Java, and I built a simple program to check whether a number is Even or Odd. 🔥 What I learned today: ✔ How to create a boolean function ✔ How to use if-else conditions inside a method ✔ How to return true/false ✔ How to call a method inside the main() function ✔ How to print the result in the console 🧩 Example I worked on: I created a method IfEven(int a) that: Prints whether the number is Even or Odd Returns a boolean value (true for even, false for odd) This helped me understand functions more clearly and how they improve code structure and reusability. #Java #LearningJourney #100DaysOfCode #Coding #Developer #JavaBeginners #OOP #CodeNewbie

🚀 Day 30 of My Java Learning Journey 📌 Topic: 3D Array in Java 🔹 Definition: A 3D array in Java is a collection of data arranged in three dimensions (layers, rows, and columns). It is like a cube of elements where each value is accessed using three indices. 🔹 Syntax: int[][][] arr = new int[2][3][4]; 🔹 Key Points: ✅ Stores data in multiple layers ✅ Useful for complex data representation ✅ Access elements using arr[i][j][k] 🔹 Example: System.out.println(arr[1][2][3]); 💡 Output: 20 📈 Learning never stops! Every day I’m getting better at Java and problem-solving. Aman Soni Vidhya Code Gurukul #Java #Programming #CodingJourney #LearningInPublic #Developers #100DaysOfCode #Tech 🚀

📚 Day 20 at Tap Academy – Learning Strings in Java Today I learned about Strings in Java, a fundamental concept used in almost every program. 🔹 What is a String? A String is a collection of characters enclosed within double quotes (" "). In Java, Strings are objects, not primitive data types. 🔹 Types of Strings ✔️ Immutable Strings - Cannot be changed once created - Example: Name, Gender, DOB ✔️ Mutable Strings - Can be modified after creation - Example: Email ID, Password 🔹 Memory Concept - Strings created using literals are stored in the String Constant Pool (SCP) - Strings created using "new" keyword are stored in Heap Memory 🔹 Ways to Create Strings String s1 = "JAVA"; String s2 = new String("JAVA"); char[] ch = {'J','A','V','A'}; String s3 = new String(ch); 🔹 String Comparison ✔️ "==" → compares reference ✔️ ".equals()" → compares values String a = "Hello"; String b = "Hello"; System.out.println(a == b); // true System.out.println(a.equals(b)); // true 💡 Key Takeaway: Strings are powerful in Java, and understanding how they work helps in writing efficient and optimized code. #Java #Programming #Coding #JavaDeveloper #LearningJourney #TapAcademy #Day20

🚀 Day 32/100 – Java Learning Journey Today’s focus was on a very important yet often overlooked concept in Java: Wrapper Classes & Cache Memory. 🔍 Key Learnings: ✔️ Wrapper Classes & Object Creation Wrapper classes like Integer, Character, etc., allow us to convert primitive data types into objects, enabling their use in collections and advanced operations. ✔️ Cache Memory in Wrapper Classes Java optimizes memory usage using cache memory for certain values. For example, Integer values between -128 to 127 are cached. 👉 Instead of creating new objects repeatedly, Java reuses existing ones — improving performance. ✔️ Important Insight When using Integer.valueOf(), Java may return a cached object. But using new Integer() always creates a new object (less efficient). ✔️ Special Case – Decimal Types Types like Float and Double do not use cache memory, which is an important distinction for optimization. 💡 Hands-on Example: Converted a string "10" into an integer using: Integer i = Integer.valueOf(s); 📌 Takeaway: Understanding internal optimizations like caching helps write efficient and memory-optimized Java code, which is crucial for real-world applications and interviews. 🔥 Consistency is key — learning something new every single day! #Java #100DaysOfCode #LearningJourney #Programming #JavaDeveloper #Coding #SoftwareDevelopment #BackendDevelopment #TechGrowth Meghana M 10000 Coders

🚀 Day 8 – Understanding Functions and Parameters in Java Today, I learned about functions (methods) in Java, which are very important for writing clean and reusable code. A function is simply a block of code that performs a specific task and can be used multiple times in a program. This helps to reduce repetition and makes the code easier to understand. I started by learning the basic syntax of a function, where we define a return type, function name, and body. Then I moved to functions with parameters, where values are passed into the function to perform operations. This made the concept more practical. Next, I learned about types of parameters: Formal Parameters: These are variables defined in the function. Actual Parameters: These are the values passed when calling the function. 👉 Understanding this difference made it clear how data flows inside a program. Overall, today’s learning helped me understand how to write better and more structured code using functions. 💪 I will keep practicing daily and improve step by step in my coding journey. #Java #Coding #DSA #Learning #Consistency

🚀 Day 7 – Practicing Java Patterns & Logic Building Today’s learning was very interesting because I focused on improving my logic-building skills using Java. I worked on different problems like checking whether a number is prime or not, and printing various patterns using loops. First, I learned how to check if a number is prime. A prime number is a number that is divisible only by 1 and itself. I used a loop to check divisibility and understood how important optimization is by using Math.sqrt(n) instead of checking all numbers. This helped me write better and efficient code. Next, I practiced star patterns using nested loops. At first, it looked confusing, but once I understood how the outer loop controls rows and the inner loop controls columns, it became easier. I learned how to print increasing and decreasing star patterns step by step. Then, I worked on a half-pyramid number pattern, where numbers increase in each row. This helped me understand how loops and conditions work together to create structured output. After that, I practiced a character pattern, where alphabets like A, B, C are printed in a structured way. It was interesting to see how characters can also be handled like numbers in Java. Finally, I also learned about using the continue statement, which helps skip certain iterations in a loop. This is useful when we want to ignore specific conditions. Overall, today’s practice helped me improve my understanding of loops, conditions, and pattern-based problems. These concepts are very important for coding interviews and problem-solving. 💪 I will keep practicing daily and improve step by step in my coding journey. #Java #Coding #DSA #LearningJourney #Consistency #ApnaCollege

☕ Learn Java with Me — Day 5 Today we’re learning: Loops in Java. Loops help us repeat a task multiple times without writing the same code again. Types we explored: → for loop → while loop → do while loop Example: for(int i = 1; i <= 5; i++) { System.out.println(i); } Output: 1 2 3 4 5 Instead of writing print 5 times, we let the loop handle it. Simple concept, but very powerful. This is where coding becomes efficient. We’re learning step by step — together 🤝 Where do you think loops can be useful? #java #coding #learning #beginners #ITstudent #showup

Day – Java Learning Update Today I learned about Multiple Inheritance and Hybrid Inheritance in Java. Multiple Inheritance means one class inherits from more than one class Hybrid Inheritance is a combination of two or more types of inheritance But Java does not support multiple and hybrid inheritance using classes Reason → Diamond Problem When two parent classes have the same method Child class gets confused which method to inherit This creates ambiguity Example flow: A → B A → C B + C → D Now D gets same method from B and C → confusion Solution in Java: Java avoids this problem by not allowing multiple inheritance with classes Instead, Java uses interfaces Interfaces provide multiple inheritance without ambiguity Key takeaway: Java focuses on simplicity and avoids confusion in method resolution #Java #JavaFullstack #OOPS #Inheritance #BackendDeveloper #LearningJourney #Programming 10000 Coders Meghana M