title: MVN compile not using UTF-8 encoding
body: <p>Ok, this is a weird problem:
  I have a java test file that uses some UTF-8 characters. When I compile it with Maven, using</p>
  
  <pre><code>mvn -Dfile.encoding=UTF-8 -Dproject.build.sourceEncoding=UTF-8 test
  </code></pre>
  
  <p>(thus setting both the perceived platform encoding and the source file encoding, see <a href="https://stackoverflow.com/questions/9976616/maven-platform-encoding">maven platform encoding</a>) I get something like</p>
  
  <pre><code>[INFO] Scanning for projects...
  [INFO] ------------------------------------------------------------------------
  [INFO] Building project
  [INFO]    task-segment: [test]
  [INFO] ------------------------------------------------------------------------
  [INFO] [resources:resources {execution: default-resources}]
  [INFO] Using 'UTF-8' encoding to copy filtered resources.
  [INFO] skip non existing resourceDirectory path/src/main/resources
  [INFO] [compiler:compile {execution: default-compile}]
  [INFO] Nothing to compile - all classes are up to date
  [INFO] [resources:testResources {execution: default-testResources}]
  [INFO] Using 'UTF-8' encoding to copy filtered resources.
  [INFO] skip non existing resourceDirectory path/src/test/resources
  [INFO] [compiler:testCompile {execution: default-testCompile}]
  [INFO] Compiling 7 source files to path/target/test-classes
  [INFO] ------------------------------------------------------------------------
  [ERROR] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Compilation failure
  path/to/file.java:[42,23] unclosed character literal
  path/to/file.java:[42,25] ';' expected
  path/to/file.java:[42,26] unclosed character literal
  path/to/file.java:[47,23] unclosed character literal
  path/to/file.java:[47,25] illegal character: \182
  path/to/file.java:[47,26] unclosed character literal
  </code></pre>
  
  <p>When I compile the file with </p>
  
  <pre><code>javac path/to/file.java
  </code></pre>
  
  <p>I get similar errors: </p>
  
  <pre><code>path/to/file.java:42: unclosed character literal
      illegalCharEnc('ä');
                     ^
  path/to/file.java:42: ';' expected
      illegalCharEnc('ä');
                       ^
  path/to/file.java:42: unclosed character literal
      illegalCharEnc('ä');
                        ^
  path/to/file.java:47: unclosed character literal
      illegalCharDec('ö');
                     ^
  path/to/file.java:47: illegal character: \182
      illegalCharDec('ö');
                       ^
  path/to/file.java:47: unclosed character literal
      illegalCharDec('ö');
                        ^
  6 errors
  </code></pre>
  
  <p>Now when I use </p>
  
  <pre><code>javac -encoding UTF-8 path/to/file.java
  </code></pre>
  
  <p>instead, I get <code>cannot find symbol</code> errors, because of the missing dependencies. So I figure the problem is that <code>javac</code> is not called with UTF-8 option in Maven when compiling tests (notice how <code>Using 'UTF-8' encoding to copy filtered resources.</code> is missing in <code>compiler:testCompile</code>-section).
  Is this conclusion correct? Am I missing something? Is this a known problem? Anything I can do about it?
  Obviously, the platform encoding on my system is not UTF-8, but I currently cannot change that.</p>