Why is Java's String class designated final?

[BarryA]

I was curious why the class java.lang.Strin g is defined as final in Java when I first learned about it. I couldn't find an answer back then, but check out this post: How to Create a Java String Class Replica. It reminded me of my question.

Sure, String gives all the functionality I've ever required, and I've never considered any action that would necessitate an extension of class String, but you never know what someone could demand!

So, does anyone know what the designers were thinking when they chose to make it final?

Scaler's blog advised me to consider the proliferation of "need a few more utility methods on String" projects that would emerge - all of which could not utilize each other's Strings since they were of a different class.

[cetpainfotech]

Java's String class is designated as final for a few reasons:

Performance: String is a very commonly used class, and making it final allows the JVM to optimize its performance by applying certain techniques such as string interning.

Security: Making the String class final prevents malicious code from creating a subclass of String and potentially modifying its behavior in a way that would compromise security.

Immutability: Strings are immutable, which means that once a String object is created, its value cannot be changed. Allowing subclasses to modify the value of a String would violate this immutability, which is a fundamental aspect of the class's behavior.

Consistency: Strings are used in many different parts of the Java standard library and in the vast majority of Java applications. Making the class final ensures that all instances of the class behave in the same way, which helps to ensure consistency and predictability in code that uses the class.

Overall, the final designation of the String class is a design decision that balances several factors, including performance, security, immutability, and consistency.