"unmappable character for encoding" warning in Java

seanhodges_43662 0
Viewed 236567

I'm currently working on a Java project that is emitting the following warning when I compile:

/src/com/myco/apps/AppDBCore.java:439: warning: unmappable character for encoding UTF8
    [javac]         String copyright = "� 2003-2008 My Company. All rights reserved.";

I'm not sure how SO will render the character before the date, but it should be a copyright symbol, and is displayed in the warning as a question mark in a diamond.

It's worth noting that the character appears in the output artifact correctly, but the warnings are a nuisance and the file containing this class may one day be touched by a text editor that saves the encoding incorrectly...

How can I inject this character into the "copyright" string so that the compiler is happy, and the symbol is preserved in the file without potential re-encoding issues?

utf-8 ascii encoding java
12 Answers

Use the "\uxxxx" escape format.

According to Wikipedia, the copyright symbol is unicode U+00A9 so your line should read:

String copyright = "\u00a9 2003-2008 My Company. All rights reserved.";
user_226560

Gradle Steps

If you are using Gradle then you can find the line that applies the java plugin:

apply plugin: 'java'

Then set the encoding for the compile task to be UTF-8:

compileJava {options.encoding = "UTF-8"}

If you have unit tests, then you probably want to compile those with UTF-8 too:

compileTestJava {options.encoding = "UTF-8"}

Overall Gradle Example

This means that the overall gradle code would look something like this:

apply plugin: 'java'
compileJava {options.encoding = "UTF-8"}
compileTestJava {options.encoding = "UTF-8"}
user_2318600

For those wondering why this happens on some systems and not on others (with the same source, build parameters, and so on), check your LANG environment variable. I get the warning/error when LANG=C.UTF-8, but not when LANG=en_US.UTF-8.

user_3204180
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