Java Immutable Strings

Strings that cannot be changed once they're created. Like a handwritten note sealed in an envelope, immutable strings preserve their content intact, ensuring consistency and reliability throughout your code.

Imagine you're writing a love letter to someone special. You want to pour your heart out onto the page, knowing that every word you write will remain as heartfelt as the moment you penned it.

Let's break it down with a simple example:

String message = "Hello";
message.concat(" World");
System.out.println(message);

In this example, you might expect the output to be "Hello World," right? After all, we're using the concat() method to add " World" to our message string. But surprise! The output is actually just "Hello." Why? Because strings in Java are immutable, meaning the concat() method doesn't change the original string—it creates a new one instead.

But wait, why would we want strings to be immutable? Well, there are a few reasons. First off, it makes them safer to use in multithreaded environments, where multiple threads might try to modify the same string simultaneously. With immutable strings, you don't have to worry about one thread messing up another thread's string.

Secondly, immutable strings are more efficient. Once a string is created, Java can reuse it whenever the same string is needed again. This saves memory and improves performance, making your programs run faster and smoother.

• Thread safety: Since immutable strings cannot be changed, they can be safely shared between multiple threads without the risk of concurrent modification.
• Memory efficiency: Immutable strings allow for string interning, where identical strings are stored in a common pool, reducing memory usage.
• Security: Immutable strings prevent unintended modification, guarding against potential security vulnerabilities.