Could not find map file

I'm using below configuration

`org.apache.maven.plugins

maven-javadoc-plugin

    <version>${maven.javadoc.plugin.version}</version>                                                       
    <configuration>
      <aggregate>true</aggregate>
      <doclet>org.umlgraph.doclet.UmlGraphDoc</doclet>                         
      <docletArtifact>                                                         
        <groupId>org.umlgraph</groupId>                                      
        <artifactId>umlgraph</artifactId>                                    
        <version>5.6</version>                                               
      </docletArtifact>`

The warning message coming while running mvn site is ..

[WARNING] Ensure that dot is in your path and that its path does not contain spaces [WARNING] java.io.IOException: Cannot run program "dot": CreateProcess error=2, The system cannot find the file specified [WARNING] at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047) [WARNING] at java.lang.Runtime.exec(Runtime.java:617) [WARNING] at java.lang.Runtime.exec(Runtime.java:485) [WARNING] at org.umlgraph.doclet.UmlGraphDoc.runGraphviz(UmlGraphDoc.java:144) [WARNING] at org.umlgraph.doclet.UmlGraphDoc.generateContextDiagrams(UmlGraphDoc.java:126) [WARNING] at org.umlgraph.doclet.UmlGraphDoc.start(UmlGraphDoc.java:68) [WARNING] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [WARNING] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [WARNING] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [WARNING] at java.lang.reflect.Method.invoke(Method.java:606) [WARNING] at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:280) [WARNING] at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:160) [WARNING] at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:397) [WARNING] at com.sun.tools.javadoc.Start.begin(Start.java:167) [WARNING] at com.sun.tools.javadoc.Main.execute(Main.java:59) [WARNING] at com.sun.tools.javadoc.Main.main(Main.java:49) [WARNING] Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified

Looking for solution I found below link -

https://issues.apache.org/jira/browse/MJAVADOC-136

Is this the fix, if yes, how to use it with same 'mvn site' command?

dspinellis / UMLGraph

Could not find map file #26