diff --git a/blackbox-test/src/main/java/org/example/customer/generics/GMS.java b/blackbox-test/src/main/java/org/example/customer/generics/GMS.java
new file mode 100644
index 00000000..790418a7
--- /dev/null
+++ b/blackbox-test/src/main/java/org/example/customer/generics/GMS.java
@@ -0,0 +1,14 @@
+package org.example.customer.generics;
+
+import io.avaje.jsonb.Json;
+
+public class GMS {
+
+  public static class Weaver {
+
+    @Json
+    public static class Hornet<T> {
+      public T value;
+    }
+  }
+}
diff --git a/blackbox-test/src/test/java/org/example/customer/generics/NestedClassGenericTest.java b/blackbox-test/src/test/java/org/example/customer/generics/NestedClassGenericTest.java
new file mode 100644
index 00000000..ddec7841
--- /dev/null
+++ b/blackbox-test/src/test/java/org/example/customer/generics/NestedClassGenericTest.java
@@ -0,0 +1,61 @@
+package org.example.customer.generics;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.LinkedHashMap;
+
+import org.example.customer.Address;
+import org.example.customer.generics.GMS.Weaver.Hornet;
+import org.junit.jupiter.api.Test;
+
+import io.avaje.jsonb.JsonType;
+import io.avaje.jsonb.Jsonb;
+import io.avaje.jsonb.Types;
+
+class NestedClassGenericTest {
+
+  Jsonb jsonb = Jsonb.instance();
+
+  private static Hornet<Address> createTestData() {
+    var bean = new Hornet<Address>();
+    bean.value = new Address(90L, "one");
+    return bean;
+  }
+
+  @SuppressWarnings({"rawtypes"})
+  @Test
+  void toJson() {
+    var bean = createTestData();
+
+    var type = jsonb.type(Hornet.class);
+
+    String asJson = type.toJson(bean);
+    assertThat(asJson).isEqualTo("{\"value\":{\"id\":90,\"street\":\"one\"}}");
+    assertThat(jsonb.toJson(bean)).isEqualTo(asJson);
+
+    var pageResult = type.fromJson(asJson);
+    Object document = pageResult.value;
+    // reading via Object means the list contains LinkedHashMap
+    assertThat(document).isInstanceOf(LinkedHashMap.class);
+    LinkedHashMap asMap = (LinkedHashMap) document;
+    assertThat(asMap.get("street")).isEqualTo("one");
+  }
+
+  @Test
+  void toJson_withGenericParam() {
+    var bean = createTestData();
+
+    JsonType<Hornet<Address>> type =
+        jsonb.type(Types.newParameterizedType(Hornet.class, Address.class));
+
+    String asJson = type.toJson(bean);
+    assertThat(asJson).isEqualTo("{\"value\":{\"id\":90,\"street\":\"one\"}}");
+    assertThat(jsonb.toJson(bean)).isEqualTo(asJson);
+
+    var genericResult = type.fromJson(asJson);
+    Address document = genericResult.value;
+
+    assertThat(document.getId()).isEqualTo(90L);
+    assertThat(document.getStreet()).isEqualTo("one");
+  }
+}
diff --git a/jsonb-generator/src/main/java/io/avaje/jsonb/generator/SimpleAdapterWriter.java b/jsonb-generator/src/main/java/io/avaje/jsonb/generator/SimpleAdapterWriter.java
index f949428b..b89129e0 100644
--- a/jsonb-generator/src/main/java/io/avaje/jsonb/generator/SimpleAdapterWriter.java
+++ b/jsonb-generator/src/main/java/io/avaje/jsonb/generator/SimpleAdapterWriter.java
@@ -57,7 +57,7 @@ void write() throws IOException {
   private void writeFactory() {
     if (genericParamsCount > 0) {
       String typeName = adapterShortName;
-      final int nestedIndex = adapterShortName.indexOf("$");
+      final int nestedIndex = adapterShortName.lastIndexOf("$");
       if (nestedIndex != -1) {
         typeName = typeName.substring(nestedIndex + 1);
       }
diff --git a/jsonb-generator/src/test/java/io/avaje/jsonb/generator/models/valid/GMS.java b/jsonb-generator/src/test/java/io/avaje/jsonb/generator/models/valid/GMS.java
new file mode 100644
index 00000000..20d7bea1
--- /dev/null
+++ b/jsonb-generator/src/test/java/io/avaje/jsonb/generator/models/valid/GMS.java
@@ -0,0 +1,14 @@
+package io.avaje.jsonb.generator.models.valid;
+
+import io.avaje.jsonb.Json;
+
+public class GMS {
+
+  public static class Weaver {
+
+    @Json
+    public static class Hornet<T> {
+      public T value;
+    }
+  }
+}