diff --git a/core/build.gradle b/core/build.gradle
index 1003ce512..d7af05b6f 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -58,12 +58,24 @@ sourceSets {
   main {
     java {
       srcDirs += generatedDir
+      // Javadoc API is deprecated and removed in Java 12.
+      // TODO(jianglai): re-enable after migrating to the new Javadoc API
+      if ((JavaVersion.current().majorVersion as Integer) > 11) {
+        exclude 'google/registry/documentation/**'
+      }
     }
     resources {
       exclude '**/*.xjb'
     }
   }
   test {
+    java {
+      // Javadoc API is deprecated and removed in Java 12.
+      // TODO(jianglai): re-enable after migrating to the new Javadoc API
+      if ((JavaVersion.current().majorVersion as Integer) > 11) {
+        exclude 'google/registry/documentation/**'
+      }
+    }
     resources {
       exclude '**/*.xjb', '**/*.xsd'
     }