By default, the Maven Javadoc Plugin tries to auto-detect the Javadoc Tool executable from the Java property java.home or from the environment variable JAVA_HOME.
You could also specify the executable of the Javadoc Tool to use with the <javadocExecutable/> parameter. For example:
<project> ... <reporting> (or <build>) <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-javadoc-plugin</artifactId> <version>2.7</version> <configuration> <javadocExecutable>C:\jdk1.6.0\bin\javadoc.exe</javadocExecutable> ... </configuration> </plugin> ... </plugins> </reporting> (or </build>) ... </project>
IMPORTANT NOTE: by using <javadocExecutable/> parameter, the build will be plateform dependent! A good practice is to define an environnement variable (i.e. JAVA_1.6_HOME), so you could specify it: (i.e. <javadocExecutable>${env.JAVA_1.6_HOME}/bin/javadoc</javadocExecutable>). An other ways is to define a POM property using <project><properties/></project>.
In the same way, the Maven Javadoc Plugin tries to auto-detect the Javadoc Tool version by calling javadoc -J-fullversion.
You could also specify the version of the Javadoc Tool executable. For example:
<project> ... <reporting> (or <build>) <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-javadoc-plugin</artifactId> <version>2.7</version> <configuration> <javadocVersion>1.5</javadocVersion> ... </configuration> </plugin> ... </plugins> </reporting> (or </build>) ... </project>
Note: You could have a warning if the javadocVersion specified is not the same that the Javadoc Tool executable.