Java final, finally and finalize

🎉 Java Fun: final, finally, and finalize Explained! 🚀

Welcome to this exciting Java tutorial where we unravel the mysteries of final, finally, and finalize. Buckle up! 🚀

---

🏆 1. Java final Keyword

The final keyword is like a "No Entry" sign for modifications. It can be applied to variables, methods, and classes, but it behaves differently in each case. Let’s explore! 🔍

🔹 1.1. final Variables – Once Set, Forever Unchanged

A variable marked final can be assigned a value only once! Here’s where you can initialize it:

✔ At the time of declaration 🏗️
✔ Inside the constructor 🏠

Code Time! ⏳

public class MyClass {
  // During declaration
  public final String MAJOR_VERSION = "1";
  public final String MINOR_VERSION;
   
  public MyClass()  {
    // In constructor
    this.MINOR_VERSION = "2";
  }
}

💡 Fact: Once initialized, trying to change a final variable will lead to a compilation error 🚨:

"The final field MyClass.VERSION cannot be assigned."

---

🔹 1.2. final Methods – No Override Allowed! 🚫

A method marked final is like a parent who says, "No, you can't change the family rules!" 🎭
It cannot be overridden by child classes.

Code Time0! ⏳

public class ParentClass {
  public final void showMyName() {
    System.out.println("In ParentClass");
  }
}

❌ Trying to override this method? Say hello to a compile-time error:

"Cannot override the final method from ParentClass."

---

🔹 1.3. final Classes – The End of Inheritance! ⛔

A final class is off-limits for inheritance. No subclasses allowed! 🚷

Code Time1! ⏳

public final class ParentClass {
  public void showMyName() {
    System.out.println("In ParentClass");
  }
}

👀 Trying to inherit from this class?

🚨 ERROR: "Cannot inherit from final ParentClass."

---

💥 2. Java finally Block – Cleanup Crew in Action! 🧹

The finally block is like that one friend who ALWAYS shows up, no matter what. Whether an exception occurs or not, this block will execute.

🛠 Use Case: Releasing Resources

✔ Closing files 📂
✔ Closing database connections 🗄️
✔ Releasing memory 🧠

Code Time2! ⏳

try {
    // Open file 📁
    // Read file 📖
}
catch(Exception e) {
    // Handle exception 🚨
}
finally {
    // Close file 🔒
}

💡 Fact: The finally block is like a janitor—it always cleans up before leaving the room! 🧽

---

🗑️ 3. Java finalize() Method – Garbage Collector’s Goodbye! 👋

⚠️ Note: Java 18 (JEP-421) has deprecated finalize(), and it will be removed in a future release! 😱

finalize() is a special method that the garbage collector calls when an object is about to be trashed! 🗑️

🔹 Defined in Object Class

protected void finalize() throws Throwable

🚀 Key Facts:

✔ Used for cleanup before the object is destroyed. 🧹
✔ If an exception is thrown in finalize(), it's ignored. 🚫
✔ finalize() is never called more than once for the same object. 🔄❌

📢 Pro Tip: Instead of finalize(), use try-with-resources or cleaners for resource management. 😎

---

🎯 4. Conclusion – The Final Showdown! 🎬

Keyword	Purpose 🎯	Can Be Used With? 🤔	Key Rule 📜
final	Restriction 🛑	Variables, Methods, Classes	No changes allowed! ❌
finally	Cleanup 🧹	Try-Catch Blocks	Always executes! 🔄
finalize()	Cleanup Before GC 🗑️	Objects	Deprecated! 🚨

💡 Fun Fact: The only thing final, finally, and finalize() have in common is… they all start with ‘final’! 🤯

---

🔥 That’s it, folks! You’re now a pro at final, finally, and finalize()! Keep coding and stay awesome! 💻✨

Happy Learning! 🚀😃