The SrcDir element in xml report generated by findbugs plugin contains source file path like a following:
<SrcDir>/path/to/project/src/main/java/package/A.java</SrcDir>
The findbugs GUI cannot display source of bug in this xml. But the GUI can display source when the SrcDir element contains directory like a following:
<SrcDir>/path/to/project/src/main/java</SrcDir>
findbugs plugin has applied sourceSet.allJava to the sourcepath parameter of findbugs. It seems incorrect. I think this plugin should apply sourceSet.java.srcDirs to this parameter.