[java] Error: unmappable character for encoding UTF8 during maven compilation

I am compiling a package using maven and it says build failure with following compilation error:

SpanishTest.java[31, 81] unmappable character for encoding UTF8

I searched online and for many people, changing source encoding from UTF-8 to ISO-8859-1 seems to work but I am still getting same compilation error. I am using 32-bit Ubuntu. Here is how that tag looks in my pom.xml

<project.build.sourceEncoding>ISO-8859-1</project.build.sourceEncoding>

Even if I change <project.build.outputEncoding> tag to ISO-8859-1, I still get the error.Could it be because of java version? I have both-sun java and openjdk installed on my system.

Can anyone please let me know what to do.

Thanks

Set incodign attribute in maven-compiler plugin work for me. The code example is the following

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    <configuration>
        <source>1.6</source>
        <target>1.6</target>
        <encoding>UTF-8</encoding>
    </configuration>
</plugin>

I came across this problem just now and ended up resolving it like so: I opened up the offending .java file in Notepad++ and from the Encoding menu I selected "Convert to UTF-8 without BOM". Saved. Re-ran maven, all went through ok.

If the offending resource was not encoded in UTF-8 - as you have configured for your maven compiler plugin - you would see in the Encoding menu of Np++ a bullet mark next to the file's current encoding (in my case I saw it was set to "Encode in ANSI").

So your maven compiler plugin invoked the Java compiler with the -encoding option set to UTF-8, but the compiler encountered a ANSI-encoded source file and reported this as an error. This used to be a warning previously in Java 5 but is treated as an error in Java 6+

I too faced a similar issue and my resolution was different. I went to the line of code mentioned and traversed to the character (For SpanishTest.java[31, 81], go to 31st line and 81th character including spaces). I observed an apostrophe in comment which was causing the issue. Though not a mistake, the maven compiler reports issue and in my case it was possible to remove maven's 'illegal' character.. lol.

This happens in the following scenario: When working on Windows, the IDE is more than likely configured to edit files in Cp1252, which is a Microsoft adaptation of latin-11. The developer checks in, and the Continuous Integration server (usually running on Linux, which nowadays is all utf8) picks up the file, and tries to compile as a UTF-8 file, hence the warning.

Try changing the encoding to cp1252. This works. To avoid future problems of this kind, use the same encoding on all the developer machines.

Good luck...

When i inspect the console i found that the version of maven compiler is 2.5.1 but in other side i try to build my project with maven 3.2.2.So after writting the exact version in pom.xml, it works good. Here is the full tag:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.2</version>
  <configuration>
   ....
  <configuration>
</plugin>

If the above answer does not work, change the encoding to cp1252 or manually remove all occurrences of the special character. For me ? special character was causing the prob which was inside a comment block.

<plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-compiler-plugin</artifactId>
   <version>2.3.2</version>
   <configuration>
       <encoding>Cp1252</encoding>
   </configuration> 
</plugin>

PS:I was using GNU/Linux OS(Ubuntu).

I guess the issues happens at the encode strings. I solved same issues. Please try adding trim() at last of the encode string.

In my case I resolved that problem using such approach:

1. Set new environment variable: JAVA_TOOL_OPTIONS = -Dfile.encoding=UTF8
2. Or set MAVEN_OPTS= -Dfile.encoding=UTF-8