diff --git a/.gitmodules b/.gitmodules
index e2584fc8396e..ae64318f51ec 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -207,3 +207,9 @@
 [submodule "community-build/community-projects/libretto"]
 	path = community-build/community-projects/libretto
 	url = https://github.com/dotty-staging/libretto.git
+[submodule "community-build/community-projects/jackson-module-scala"]
+	path = community-build/community-projects/jackson-module-scala
+	url = https://github.com/FasterXML/jackson-module-scala.git
+[submodule "community-build/community-projects/scala-java8-compat"]
+	path = community-build/community-projects/scala-java8-compat
+	url = https://github.com/scala/scala-java8-compat.git
diff --git a/community-build/community-projects/jackson-module-scala b/community-build/community-projects/jackson-module-scala
new file mode 160000
index 000000000000..13e3a34a46d6
--- /dev/null
+++ b/community-build/community-projects/jackson-module-scala
@@ -0,0 +1 @@
+Subproject commit 13e3a34a46d60dfcc0a787b46c73f2f3cd6cc379
diff --git a/community-build/community-projects/scala-java8-compat b/community-build/community-projects/scala-java8-compat
new file mode 160000
index 000000000000..57e1f7ccaa67
--- /dev/null
+++ b/community-build/community-projects/scala-java8-compat
@@ -0,0 +1 @@
+Subproject commit 57e1f7ccaa67dcac2b4227ab1a6ee0fcb5f42023
diff --git a/community-build/src/scala/dotty/communitybuild/projects.scala b/community-build/src/scala/dotty/communitybuild/projects.scala
index 32d9cbed45df..6d31cd73b54c 100644
--- a/community-build/src/scala/dotty/communitybuild/projects.scala
+++ b/community-build/src/scala/dotty/communitybuild/projects.scala
@@ -508,6 +508,14 @@ object projects:
     sbtPublishCommand = "compat30/publishLocal",
   )
 
+  lazy val scalaJava8Compat = SbtCommunityProject(
+    project        = "scala-java8-compat",
+    // the fnGen subproject must be built with 2.12.x
+    sbtTestCommand = s"++2.12.14; ++$compilerVersion; set fnGen/dependencyOverrides := Nil; test",
+    sbtPublishCommand = s"++2.12.14; ++$compilerVersion; set fnGen/dependencyOverrides := Nil; publishLocal",
+    scalacOptions = Nil // avoid passing Scala 3 options to Scala 2.12 in fnGen subproject
+  )
+
   lazy val verify = SbtCommunityProject(
     project        = "verify",
     sbtTestCommand = "verifyJVM/test",
@@ -716,6 +724,13 @@ object projects:
     dependencies = List(scalatest)
   )
 
+  lazy val jacksonModuleScala = SbtCommunityProject(
+    project = "jackson-module-scala",
+    sbtTestCommand = "test",
+    sbtPublishCommand = "publishLocal",
+    dependencies = List(scalaJava8Compat, scalatest)
+  )
+
 end projects
 
 def allProjects = List(
@@ -762,6 +777,7 @@ def allProjects = List(
   projects.catsEffect3,
   projects.scalaParallelCollections,
   projects.scalaCollectionCompat,
+  projects.scalaJava8Compat,
   projects.verify,
   projects.discipline,
   projects.disciplineMunit,
@@ -792,6 +808,7 @@ def allProjects = List(
   projects.scalacheckEffect,
   projects.fs2,
   projects.libretto,
+  projects.jacksonModuleScala,
 )
 
 lazy val projectMap = allProjects.groupBy(_.project)
diff --git a/community-build/test/scala/dotty/communitybuild/CommunityBuildTest.scala b/community-build/test/scala/dotty/communitybuild/CommunityBuildTest.scala
index 507920c7cc4b..62535a22f286 100644
--- a/community-build/test/scala/dotty/communitybuild/CommunityBuildTest.scala
+++ b/community-build/test/scala/dotty/communitybuild/CommunityBuildTest.scala
@@ -145,6 +145,7 @@ class CommunityBuildTestC extends CommunityBuildTest:
   @Test def fastparse = projects.fastparse.run()
   @Test def geny = projects.geny.run()
   @Test def intent = projects.intent.run()
+  @Test def jacksonModuleScala = projects.jacksonModuleScala.run()
   @Test def libretto = projects.libretto.run()
   @Test def minitest = projects.minitest.run()
   @Test def onnxScala = projects.onnxScala.run()
@@ -156,6 +157,7 @@ class CommunityBuildTestC extends CommunityBuildTest:
   @Test def requests = projects.requests.run()
   @Test def scalacheck = projects.scalacheck.run()
   @Test def scalaCollectionCompat = projects.scalaCollectionCompat.run()
+  @Test def scalaJava8Compat = projects.scalaJava8Compat.run()
   @Test def scalap = projects.scalap.run()
   @Test def scalaParallelCollections = projects.scalaParallelCollections.run()
   @Test def scalaParserCombinators = projects.scalaParserCombinators.run()