Use central javadoc-options file

buildSrc/src/main/groovy/com/jozufozu/gradle/OutgoingConfigurationPlugin.groovy

@@ -74,6 +74,7 @@ class OutgoingConfigurationPlugin implements Plugin<Project> {
                 group = 'Build'
                 destinationDir = project.layout.buildDirectory.dir("docs/${name}-javadoc").get().asFile
                 options.encoding = 'UTF-8'
+                options.optionFiles(project.rootProject.file('javadoc-options.txt'))
                 for (SourceSet set in sourceSetSet) {
                     source set.allJava
                     classpath += set.compileClasspath

buildSrc/src/main/groovy/flywheel.java.gradle

@@ -43,7 +43,7 @@ tasks.withType(Jar).configureEach { Jar jar ->
 tasks.named('javadoc', Javadoc).configure { Javadoc javadoc ->
     javadoc.source sourceSets.main.allJava
     // prevent java 8's strict doclint for javadocs from failing builds
-    javadoc.options.addStringOption('Xdoclint:none', '-quiet')
+    javadoc.options.optionFiles(rootProject.file('javadoc-options.txt'))
     javadoc.options.encoding = 'UTF-8'
 }
 

javadoc-options.txt

@@ -0,0 +1,2 @@
+-Xdoclint:none
+-quiet