I've been using the section sign (§) to make my item tooltips a bit more colorful. I've been doing this using Item#addInformation. The formatting works perfectly in the development environment, but whenever I build the mod and use it in the actual game, it bugs out and seems to replace all the section signs with another unintelligible symbol, resulting in no formatting taking place. What's wrong?

You need to make Gradle compile your code as UTF-8 by adding this to build.gradle:

tasks.withType(JavaCompile) {
    options.encoding = 'UTF-8'
}

I added that to the end of the file (since you didn't specify a location), but it's just replaced the unintelligible character with a '?' in a white square.

Type '\u00a7' instead of the section sign. Java doesn't like symbols, so it's best to pass the unicode index from the JVM to the system.

Like diesieben07 said, it will work if you use UTF-8 everywhere. I assumed that your code was already saved as UTF-8, I didn't realise that the section sign is also present in older encodings like Windows-1252.

 

You can see an example of this here (lang file is here). It looks like this in the obfuscated client.

 

Edit: Added missing closing tag