As of JDK 13, the com.sun.javadoc API is no longer supported.
diff --git a/src/it/projects/MJAVADOC-427/verify.groovy b/src/it/projects/MJAVADOC-427/verify.groovy
index 035c4d6..f3ad4b0 100644
--- a/src/it/projects/MJAVADOC-427/verify.groovy
+++ b/src/it/projects/MJAVADOC-427/verify.groovy
@@ -23,4 +23,4 @@
 
 // assert that javadoc of class correctly contains link, just like method details
 assert file.text =~ /Link to slf4j <a href=".*?".*?><code>LoggerFactory<\/code><\/a>/
-assert file.text =~ /<pre[^<]*>public.*?<a href=".*?".*?>LoggerFactory<\/a>.*?getLoggerFactory.*?\(\)<\/pre>/
+assert file.text =~ /public.*?<a href=".*?".*?>LoggerFactory<\/a>.*?getLoggerFactory.*?\(\)/
diff --git a/src/it/projects/MJAVADOC-514_3rdparty-doclettags/invoker.properties b/src/it/projects/MJAVADOC-514_3rdparty-doclettags/invoker.properties
index 22c9049..50fc310 100644
--- a/src/it/projects/MJAVADOC-514_3rdparty-doclettags/invoker.properties
+++ b/src/it/projects/MJAVADOC-514_3rdparty-doclettags/invoker.properties
@@ -15,4 +15,6 @@
 # specific language governing permissions and limitations
 # under the License.
 
-invoker.goals=clean javadoc:javadoc
+invoker.goals=javadoc:javadoc
+# As of JDK 13, the com.sun.javadoc API is no longer supported.
+invoker.java.version = 13-
diff --git a/src/it/projects/additional-dependencies-non-aggregate/invoker.properties b/src/it/projects/additional-dependencies-non-aggregate/invoker.properties
index eca1aa7..a78a9f0 100644
--- a/src/it/projects/additional-dependencies-non-aggregate/invoker.properties
+++ b/src/it/projects/additional-dependencies-non-aggregate/invoker.properties
@@ -16,4 +16,5 @@
 # under the License.
 
 invoker.goals=clean site
-invoker.java.version = 1.6+
+# As of JDK 13, the com.sun.javadoc API is no longer supported.
+invoker.java.version = 13-
diff --git a/src/it/projects/additional-dependencies/invoker.properties b/src/it/projects/additional-dependencies/invoker.properties
index eca1aa7..a78a9f0 100644
--- a/src/it/projects/additional-dependencies/invoker.properties
+++ b/src/it/projects/additional-dependencies/invoker.properties
@@ -16,4 +16,5 @@
 # under the License.
 
 invoker.goals=clean site
-invoker.java.version = 1.6+
+# As of JDK 13, the com.sun.javadoc API is no longer supported.
+invoker.java.version = 13-
diff --git a/src/test/java/org/apache/maven/plugins/javadoc/JavadocReportTest.java b/src/test/java/org/apache/maven/plugins/javadoc/JavadocReportTest.java
index 55bb3d6..765ff16 100644
--- a/src/test/java/org/apache/maven/plugins/javadoc/JavadocReportTest.java
+++ b/src/test/java/org/apache/maven/plugins/javadoc/JavadocReportTest.java
@@ -457,6 +457,12 @@
     public void testDoclets()
         throws Exception
     {
+        if ( JavaVersion.JAVA_SPECIFICATION_VERSION.isAtLeast( "13" ) )
+        {
+            // As of JDK 13, the com.sun.javadoc API is no longer supported.
+            return;
+        }
+  
         // ----------------------------------------------------------------------
         // doclet-test: check if the file generated by UmlGraph exists and if
         // doclet path contains the UmlGraph artifact
@@ -464,7 +470,7 @@
 
         File testPom = new File( unit, "doclet-test/doclet-test-plugin-config.xml" );
         JavadocReport mojo = lookupMojo( testPom );
-
+  
         MavenSession session = spy( newMavenSession( mojo.project ) );
         ProjectBuildingRequest buildingRequest = mock( ProjectBuildingRequest.class );
         when( buildingRequest.getRemoteRepositories() ).thenReturn( mojo.project.getRemoteArtifactRepositories() );
@@ -763,7 +769,7 @@
         assertTrue( content.contains( "<img src=\"doc-files/maven-feather.png\" alt=\"Maven\">" ) );
 
         JavaVersion javadocVersion = (JavaVersion) getVariableValueFromObject( mojo, "javadocRuntimeVersion" );
-        if( javadocVersion.isAtLeast( "1.8" ) && javadocVersion.isBefore( "13" ) )
+        if( javadocVersion.isAtLeast( "1.8" ) && javadocVersion.isBefore( "14" ) )
         {
             // https://bugs.openjdk.java.net/browse/JDK-8032205
             assertTrue( "Javadoc runtime version: " + javadocVersion
@@ -1238,7 +1244,13 @@
         mojo.execute();
 
         String content = readFile( stylesheetfile );
-        if ( JavaVersion.JAVA_VERSION.isAtLeast( "10" ) )
+        if ( JavaVersion.JAVA_VERSION.isAtLeast( "13-ea" ) )
+        {
+            assertTrue( content.contains( "/*" + LINE_SEPARATOR
+                                        + " * Javadoc style sheet" + LINE_SEPARATOR
+                                        + " */" ) );
+        }
+        else if ( JavaVersion.JAVA_VERSION.isAtLeast( "10" ) )
         {
             assertTrue( content.contains( "/* " + LINE_SEPARATOR
                                         + " * Javadoc style sheet" + LINE_SEPARATOR