diff --git a/cast/java/test/data/build.gradle.kts b/cast/java/test/data/build.gradle.kts
index 8bf1cae4d5..b773d3ea47 100644
--- a/cast/java/test/data/build.gradle.kts
+++ b/cast/java/test/data/build.gradle.kts
@@ -45,11 +45,15 @@ val downloadJLex by
     tasks.registering(VerifiedDownload::class) {
       src = URL("https://www.cs.princeton.edu/~appel/modern/java/JLex/current/Main.java")
       checksum = "fe0cff5db3e2f0f5d67a153cf6c783af"
-      val downloadedSourceDir by extra(layout.buildDirectory.dir(name))
-      dest = downloadedSourceDir.map { it.file("JLex/Main.java") }
+      val downloadedSourceDir = layout.buildDirectory.dir(name).map(Directory::toString)
+      inputs.property("downloadedSourceDir", downloadedSourceDir)
+      dest = layout.buildDirectory.dir(name).map { it.file("JLex/Main.java") }
     }
 
-sourceSets.test.get().java.srcDir(downloadJLex.map { it.extra["downloadedSourceDir"]!! })
+sourceSets.test
+    .get()
+    .java
+    .srcDir(downloadJLex.map { it.inputs.properties["downloadedSourceDir"]!! })
 
 ////////////////////////////////////////////////////////////////////////
 //
diff --git a/core/build.gradle.kts b/core/build.gradle.kts
index ea2738060b..54392228f0 100644
--- a/core/build.gradle.kts
+++ b/core/build.gradle.kts
@@ -172,7 +172,8 @@ val buildKawaTestJar by
 
 val downloadBcel by
     tasks.registering(VerifiedDownload::class) {
-      val basename by extra("bcel-5.2")
+      val basename = "bcel-5.2"
+      inputs.property("basename", basename)
       val archive = "${basename}.tar.gz"
       src = URL("https://archive.apache.org/dist/jakarta/bcel/binaries/$archive")
       dest = project.layout.buildDirectory.file(archive)
@@ -182,7 +183,7 @@ val downloadBcel by
 
 val extractBcel by
     tasks.registering {
-      val basename = downloadBcel.map { it.extra["basename"] as String }
+      val basename = downloadBcel.map { it.inputs.properties["basename"] as String }
       val jarFile = basename.flatMap { layout.buildDirectory.file("$name/${it}.jar") }
       inputs.files(downloadBcel.map { it.outputs.files })
       outputs.file(jarFile)