Checkstyle with checkstyle 9.3

build.gradle

@@ -70,11 +70,18 @@ test {
     }
 }
 
+tasks.withType(Checkstyle) {
+    reports {
+        // Not to skip up-to-date checkstyles.
+        outputs.upToDateWhen { false }
+    }
+}
+
 checkstyle {
-    toolVersion "8.23"
-    configFile = file("${projectDir}/config/checkstyle/checkstyle.xml")
+    toolVersion "9.3"
+    configFile = file("${rootProject.projectDir}/config/checkstyle/checkstyle.xml")
     configProperties = [
-        "checkstyle.config.path": file("${projectDir}/config/checkstyle")
+        "org.checkstyle.google.suppressionfilter.config": file("${rootProject.projectDir}/config/checkstyle/checkstyle-suppressions.xml"),
     ]
     ignoreFailures = false
     maxWarnings = 0

config/checkstyle/README.md

@@ -1,11 +1,11 @@
 Checkstyle for the Embulk project
 ==================================
 
-* google_check.xml: Downloaded from: https://github.com/checkstyle/checkstyle/blob/master/src/main/resources/google_checks.xml
-     * Commit: e145aa1c2829f1bc3cccb879dd5197a4904f5687
+* google_check.xml: Downloaded from: https://github.com/checkstyle/checkstyle/blob/checkstyle-9.3/src/main/resources/google_checks.xml
+     * Commit: 5c1903792f8432243cc8ae5cd79a03a004d3c09c
 * checkstyle.xml: Customized from google_check.xml.
+    * To enable suppressions through checkstyle-suppressions.xml.
     * To enable suppressions with @SuppressWarnings.
-    * To accept package names with underscores.
     * To indent with 4-column spaces.
-    * To limit columns to 180 characters, which will be shortened later.
+    * To limit columns to 180 characters.
     * To reject unused imports.

config/checkstyle/suppressions.xml → config/checkstyle/checkstyle-suppressions.xml

@@ -1,13 +1,15 @@
 <?xml version="1.0"?>
 
 <!DOCTYPE suppressions PUBLIC
-    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
-    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
+    "-//Puppy Crawl//DTD Suppressions 1.2//EN"
+    "http://checkstyle.sourceforge.net/dtds/suppressions_1_2.dtd">
 
 <suppressions>
   <suppress checks="JavadocMethod" files=".*"/>
   <suppress checks="JavadocParagraph" files=".*"/>
   <suppress checks="JavadocTagContinuationIndentation" files=".*"/>
+  <suppress checks="MissingJavadocType" files=".*"/>
+  <suppress checks="PackageName" files=".*"/>
   <suppress checks="SingleLineJavadoc" files=".*"/>
   <suppress checks="SummaryJavadoc" files=".*"/>
 </suppressions>