diff --git a/afterburner/src/test/java/tools/jackson/module/afterburner/ser/CustomBeanPropertyWriterTest.java b/afterburner/src/test/java/tools/jackson/module/afterburner/ser/CustomBeanPropertyWriterTest.java
index acc4ac84..e32e3884 100644
--- a/afterburner/src/test/java/tools/jackson/module/afterburner/ser/CustomBeanPropertyWriterTest.java
+++ b/afterburner/src/test/java/tools/jackson/module/afterburner/ser/CustomBeanPropertyWriterTest.java
@@ -27,6 +27,8 @@ public SampleObject(String field1, Integer field2, Integer field3) {
     }
 
     static class Only2BeanSerializerModifier extends ValueSerializerModifier {
+        private static final long serialVersionUID = 1L;
+
         @Override
         public List<BeanPropertyWriter> changeProperties(SerializationConfig config, BeanDescription beanDesc, List<BeanPropertyWriter> props)
         {
diff --git a/android-record/src/test/java/tools/jackson/module/androidrecord/AndroidRecordTest.java b/android-record/src/test/java/tools/jackson/module/androidrecord/AndroidRecordTest.java
index b4348193..220e1010 100644
--- a/android-record/src/test/java/tools/jackson/module/androidrecord/AndroidRecordTest.java
+++ b/android-record/src/test/java/tools/jackson/module/androidrecord/AndroidRecordTest.java
@@ -74,8 +74,8 @@ public boolean equals(Object o) {
   }
 
   static final class MultipleConstructors extends RecordTag {
-    final int i;
-    final List<String> l;
+    private final int i;
+    private final List<String> l;
 
     MultipleConstructors(int i, List<String> l) {
       this.i = i;
diff --git a/blackbird/src/main/java/tools/jackson/module/blackbird/deser/BBDeserializerModifier.java b/blackbird/src/main/java/tools/jackson/module/blackbird/deser/BBDeserializerModifier.java
index 8623a3f7..9b63d2a5 100644
--- a/blackbird/src/main/java/tools/jackson/module/blackbird/deser/BBDeserializerModifier.java
+++ b/blackbird/src/main/java/tools/jackson/module/blackbird/deser/BBDeserializerModifier.java
@@ -27,6 +27,8 @@
 
 public class BBDeserializerModifier extends ValueDeserializerModifier
 {
+    private static final long serialVersionUID = 1L;
+
     private static final MethodHandle TRAMPOLINE, BOOLEAN_TRAMPOLINE, LONG_TRAMPOLINE, INT_TRAMPOLINE;
 
     static {
diff --git a/blackbird/src/main/java/tools/jackson/module/blackbird/ser/BBSerializerModifier.java b/blackbird/src/main/java/tools/jackson/module/blackbird/ser/BBSerializerModifier.java
index 37a05e8f..33444460 100644
--- a/blackbird/src/main/java/tools/jackson/module/blackbird/ser/BBSerializerModifier.java
+++ b/blackbird/src/main/java/tools/jackson/module/blackbird/ser/BBSerializerModifier.java
@@ -25,6 +25,8 @@
 
 public class BBSerializerModifier extends ValueSerializerModifier
 {
+    private static final long serialVersionUID = 1L;
+
     private final Function<Class<?>, Lookup> _lookups;
     private final UnaryOperator<Lookup> _accessGrant;
 
diff --git a/blackbird/src/test/java/tools/jackson/module/blackbird/ser/CustomBeanPropertyWriterTest.java b/blackbird/src/test/java/tools/jackson/module/blackbird/ser/CustomBeanPropertyWriterTest.java
index 6e927926..1ada626b 100644
--- a/blackbird/src/test/java/tools/jackson/module/blackbird/ser/CustomBeanPropertyWriterTest.java
+++ b/blackbird/src/test/java/tools/jackson/module/blackbird/ser/CustomBeanPropertyWriterTest.java
@@ -29,6 +29,8 @@ public SampleObject(String field1, Integer field2, Integer field3) {
     }
 
     static class Only2BeanSerializerModifier extends ValueSerializerModifier {
+        private static final long serialVersionUID = 1L;
+
         @Override
         public List<BeanPropertyWriter> changeProperties(SerializationConfig config, BeanDescription beanDesc, List<BeanPropertyWriter> props)
         {
diff --git a/jaxb/src/test/java/tools/jackson/module/jaxb/misc/TestDeserializerCaching.java b/jaxb/src/test/java/tools/jackson/module/jaxb/misc/TestDeserializerCaching.java
index 1806a4df..ac4aef87 100644
--- a/jaxb/src/test/java/tools/jackson/module/jaxb/misc/TestDeserializerCaching.java
+++ b/jaxb/src/test/java/tools/jackson/module/jaxb/misc/TestDeserializerCaching.java
@@ -41,6 +41,8 @@ static class MyType {
     
     static class MyBeanDeserializerModifier extends ValueDeserializerModifier
     {
+        private static final long serialVersionUID = 1L;
+
         static int count = 0;
 
         @Override