Strings no longer immutable?

[twisst]

Select the type of content error.

Factual Mistake

Section

Tutorials

Location of the error

https://processing.org/tutorials/text

Describe the error

Are Strings in Processing still immutable or has that changed? I am by no means an expert Java programmer, but the section by Dan on Strings being immutable (dated 2008) seems to be no longer true. I can do this no problem:

String message = "bleep bloop"; message = message.toUpperCase(); println(message); // BLEEP BLOOP

Suggested correction

Simply replace the paragraphs below by:

The method toUpperCase() returns a copy of the String object with all caps. If you want the original String to be changed to all-caps, then assign the result to message:

String message = "bleep bloop"; message = message.toUpperCase(); println(message); // BLEEP BLOOP

Language

English

Screenshots or references

Current paragraphs: "You might notice something a bit odd here. Why didn't we simply say message.toUpperCase() and then print message variable? Instead, we assigned the result of message.toUpperCase() to a new variable with a different name—uppercase.

This is because a String is a special kind of object. It is immutable. An immutable object is one whose data can never be changed. Once we create a String, it stays the same for life. Anytime we want to change the String, we have to create a new one. So in the case of converting to uppercase, the method toUpperCase() returns a copy of the String object with all caps."

Additional context

No response

[SableRaf]

Hi @twisst and thank you for bringing this up! You're correct that the example works because the result of toUpperCase() is reassigned to the variable message, but this doesn't change the fact that String objects in Java are immutable.

The sentence in the tutorial:

Why didn't we simply say message.toUpperCase() and then print the message variable?

aims to clarify a potential misunderstanding: .toUpperCase() does not modify the original message directly but instead returns a new String object.

That said, the explanation could be updated to make this behavior clearer and avoid confusion.

If you're interested, you can propose a change by creating a pull request to update the tutorial with your suggestion. If you need help with submitting a PR or have questions about the process, feel free to reach out!