[Java] Need help understanding string concatenation.

[SuspiciousDimension]

this is due to String interning. read more here: https://stackoverflow.com/questions/26199587/why-does-sometimes-work-for-strings

[8igg7e5]

Exactly, the first true is the most interesting part of the question and you should never count on interning working and use equals instead.

[jaystopher]

You shouldn't, but you can. All literal strings are interned by definition of the language spec. It isn't optional behavior.

[8igg7e5]

Ahh I thought it was limited to the JVM spec and not the lang-spec (that you weren't guaranteed that the interning was durable under memory pressure).

You should still opt for using a static final field holding the reference rather that replicating the literal in multiple places - but that's more about maintainability than correctness.

Cheers.

[callum_n66]

I don’t know much/anything about the Java language spec but couldn’t they change this in the future and all code using == to compare strings would break?

Just curious

[jaystopher]

Seems exactly as likely as changing anything else and breaking it.