diff --git a/build-logic/src/main/groovy/org/apache/groovy/gradle/GroovyLibraryExtension.groovy b/build-logic/src/main/groovy/org/apache/groovy/gradle/GroovyLibraryExtension.groovy
index e5eea8d1a5a..3a8d2322f13 100644
--- a/build-logic/src/main/groovy/org/apache/groovy/gradle/GroovyLibraryExtension.groovy
+++ b/build-logic/src/main/groovy/org/apache/groovy/gradle/GroovyLibraryExtension.groovy
@@ -106,7 +106,8 @@ class GroovyLibraryExtension {
                     Map<String, String> mappingPatterns,
                     Map<String, List<String>> libraryExcludes,
                     List<String> allExcludes,
-                    Map<String, String> resources
+                    Map<String, String> resources,
+                    Map<String, List<String>> relocationExcludes = [:]
     ) {
         grooid.set(true)
         def grooidJar = tasks.register("grooidJar", RepackageJarTask) {
@@ -125,6 +126,7 @@ class GroovyLibraryExtension {
                 }.files
             }
             it.patterns = mappingPatterns
+            it.relocationExcludes = relocationExcludes
             it.excludesPerLibrary = libraryExcludes
             it.sourceExcludes = allExcludes
             it.generateOsgiManifest = false
diff --git a/build-logic/src/main/groovy/org/apache/groovy/gradle/RepackageJarTask.groovy b/build-logic/src/main/groovy/org/apache/groovy/gradle/RepackageJarTask.groovy
index e91a1f56537..169eee0010b 100644
--- a/build-logic/src/main/groovy/org/apache/groovy/gradle/RepackageJarTask.groovy
+++ b/build-logic/src/main/groovy/org/apache/groovy/gradle/RepackageJarTask.groovy
@@ -89,6 +89,23 @@ abstract class RepackageJarTask extends ShadowJar {
     @Input
     Map<String, String> patterns = [:]
 
+    /**
+     * Classes left untouched by a relocation pattern, keyed by the pattern
+     * ({@code 'java.beans.**': ['java.beans.Transient']}): a type the JDK has but
+     * the repackaged replacement library does not, so rewriting the reference
+     * would point at a class that never exists (GROOVY-12391).
+     * <p>
+     * Values are passed to Shadow's relocator exclusion as given. Shadow accepts
+     * the dotted class name used here as well as the slashed internal form and
+     * its {@code *} / {@code **} patterns, normalising all of them before
+     * matching. An exclusion that did not apply would not fail silently: the
+     * root build's {@code grooidJar} task checks the produced jar still
+     * references {@code java.beans.Transient}.
+     */
+    @Input
+    @Optional
+    Map<String, List<String>> relocationExcludes = [:]
+
     @Input
     @Optional
     Map<String, List<String>> excludesPerLibrary = [:]
@@ -223,10 +240,11 @@ abstract class RepackageJarTask extends ShadowJar {
             // rewritten to groovyjarjaropenbeans the lookup no-ops. Type/descriptor
             // remapping is unaffected (skipStringConstants only gates LDC strings).
             // See GROOVY-12199 / Bucket 4a.
-            if (shouldSkipStringConstants(prefix)) {
-                relocate(prefix, destination) { it.skipStringConstants = true }
-            } else {
-                relocate(prefix, destination)
+            List<String> untouched = relocationExcludes[pattern] ?: []
+            boolean skipStrings = shouldSkipStringConstants(prefix)
+            relocate(prefix, destination) { relocator ->
+                if (skipStrings) relocator.skipStringConstants = true
+                untouched.each { relocator.exclude(it) }
             }
         }
 
diff --git a/build.gradle b/build.gradle
index 1448627bd1e..afcd4be07a2 100644
--- a/build.gradle
+++ b/build.gradle
@@ -56,10 +56,33 @@ groovyLibrary {
             ['META-INF/NOTICE', 'META-INF/INDEX.LIST'],
             [
                     (project.relativePath(rootProject.file('notices/NOTICE-GROOIDJARJAR'))): 'META-INF/NOTICE'
+            ],
+            [
+                    // openbeans predates java.beans.Transient (Java 7); rewriting the annotation
+                    // would point at a class that does not exist and break the Verifier (GROOVY-12391)
+                    'java.beans.**': ['java.beans.Transient']
             ]
     )
 }
 
+// GROOVY-12391: the exclusion above must hold in the produced jar, or the grooid jar
+// cannot compile anything (the Verifier resolves the annotation class when it loads)
+tasks.named('grooidJar') {
+    doLast {
+        def jar = new java.util.zip.ZipFile(archiveFile.get().asFile)
+        try {
+            ['groovy/lang/GroovyObjectSupport.class', 'org/codehaus/groovy/classgen/Verifier.class'].each { entry ->
+                def bytes = new String(jar.getInputStream(jar.getEntry(entry)).bytes, 'ISO-8859-1')
+                if (bytes.contains('groovyjarjaropenbeans/Transient') || !bytes.contains('java/beans/Transient')) {
+                    throw new GradleException("$entry in the grooid jar must keep referencing java.beans.Transient")
+                }
+            }
+        } finally {
+            jar.close()
+        }
+    }
+}
+
 groovyCore {
     def supportClasses = ['Boolean','Char','Byte','Short','Int','Long','Float','Double'].collect {
         'org.codehaus.groovy.transform.stc.StaticTypeCheckingSupport$'+it+'ArrayStaticTypesHelper'