I'm using OpenJDK 11 on Windows 10. I have a very simple POM, for a single Java file, that generates Javadocs. Here is an extract:
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>3.0.1</version>
<executions>
<execution>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Strangely just running mvn clean package
causes an error:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.0.1:jar (default) on project foobar: MavenReportException: Error while generating Javadoc:
[ERROR] Exit code: 1 - javadoc: error - cannot read Input length = 1
[ERROR]
[ERROR] Command line was: C:\bin\jdk-11\bin\javadoc.exe @options @packages
In target/apidocs
there are only three files: javadoc.bat
, options
, and packages
. The options
file is the most interesting. It explicitly says UTF-8
everywhere, as it should. But look at these lines:
-sourcepath
C:/projects/li��o 1/src/main/java
This project is in C:\projects\lição 1
. It appears that somewhere along the chain Java or Maven or the Javadoc plugin didn't correctly convert the directory name to UTF-8.
Sure enough; when I renamed the directories in Windows to remove non-ASCII characters, mvn clean package
worked just fine.
This would seem like a blatant bug; once Maven starts, everything should be UTF-8 throughout. Is it a problem with the Javadoc plugin? Anyone have an idea where this originates? Where should I file a bug ticket? Or am I doing something wrong?
As you say, this looks like the encoding used to write the files to target/apidocs
.
Looking through the source for the maven-javadoc-plugin, it is just using the platform encoding when writing these files - e.g. this line.
Directly setting the encoding while calling Maven repaired the example above for me:
mvn clean package -Dfile.encoding=UTF-8
This feels more like a workaround than a good fix though - it needs to assume there is nothing else depending on the platform encoding in the Maven build.
I think the cause is a change in the main JDK between 8 and 9. The bit of code (actually under javac) that parses the argument files (e.g. @options
in the javadoc command line) has switched from using the platform encoding here to calling Files.newBufferedReader()
here. Files.newBufferedReader(Path) states that it uses UTF-8 if the encoding is not specified. This means argument files, in both javac and javadoc, must now be encoded in UTF-8.
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