diff --git a/plugin/trino-kafka-event-listener/pom.xml b/plugin/trino-kafka-event-listener/pom.xml
index d322443e93f2..dcba886d4a6d 100644
--- a/plugin/trino-kafka-event-listener/pom.xml
+++ b/plugin/trino-kafka-event-listener/pom.xml
@@ -13,6 +13,10 @@
     <packaging>trino-plugin</packaging>
     <description>Trino - Kafka Event Listener</description>
 
+    <properties>
+        <air.compiler.fail-warnings>true</air.compiler.fail-warnings>
+    </properties>
+
     <dependencies>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
diff --git a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventListener.java b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventListener.java
index 98133b2a92a2..320631d90796 100644
--- a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventListener.java
+++ b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventListener.java
@@ -59,10 +59,8 @@ public KafkaEventListener(KafkaEventListenerConfig config, KafkaProducerFactory
             if (config.getTerminateOnInitializationFailure()) {
                 throw e;
             }
-            else {
-                LOG.error(e, "Failed to initialize Kafka publisher.");
-                stats.kafkaPublisherFailedToInitialize();
-            }
+            LOG.error(e, "Failed to initialize Kafka publisher.");
+            stats.kafkaPublisherFailedToInitialize();
         }
     }
 
diff --git a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventPublisher.java b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventPublisher.java
index 8678c184c659..7f94adfc6782 100644
--- a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventPublisher.java
+++ b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/KafkaEventPublisher.java
@@ -78,9 +78,7 @@ private MetadataProvider metadataProvider(KafkaEventListenerConfig config)
         if (config.getEnvironmentVariablePrefix().isPresent()) {
             return new EnvMetadataProvider(config.getEnvironmentVariablePrefix().get());
         }
-        else {
-            return new NoOpMetadataProvider();
-        }
+        return new NoOpMetadataProvider();
     }
 
     public void publishCompletedEvent(QueryCompletedEvent queryCompletedEvent)
diff --git a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCompletedEventWrapper.java b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCompletedEventWrapper.java
index ecd23096a612..4c9c12f536c8 100644
--- a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCompletedEventWrapper.java
+++ b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCompletedEventWrapper.java
@@ -14,6 +14,7 @@
 
 package io.trino.plugin.eventlistener.kafka.model;
 
+import com.google.common.collect.ImmutableMap;
 import io.trino.spi.eventlistener.QueryCompletedEvent;
 
 import java.util.Map;
@@ -25,6 +26,6 @@ public record QueryCompletedEventWrapper(QueryCompletedEvent eventPayload, Map<S
     public QueryCompletedEventWrapper
     {
         requireNonNull(eventPayload, "eventPayload is null");
-        requireNonNull(eventMetadata, "eventMetadata is null");
+        eventMetadata = ImmutableMap.copyOf(requireNonNull(eventMetadata, "eventMetadata is null"));
     }
 }
diff --git a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCreatedEventWrapper.java b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCreatedEventWrapper.java
index f073c1bde049..5c04637a6aca 100644
--- a/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCreatedEventWrapper.java
+++ b/plugin/trino-kafka-event-listener/src/main/java/io/trino/plugin/eventlistener/kafka/model/QueryCreatedEventWrapper.java
@@ -14,6 +14,7 @@
 
 package io.trino.plugin.eventlistener.kafka.model;
 
+import com.google.common.collect.ImmutableMap;
 import io.trino.spi.eventlistener.QueryCreatedEvent;
 
 import java.util.Map;
@@ -25,6 +26,6 @@ public record QueryCreatedEventWrapper(QueryCreatedEvent eventPayload, Map<Strin
     public QueryCreatedEventWrapper
     {
         requireNonNull(eventPayload, "eventPayload is null");
-        requireNonNull(eventMetadata, "eventMetadata is null");
+        eventMetadata = ImmutableMap.copyOf(requireNonNull(eventMetadata, "eventMetadata is null"));
     }
 }
diff --git a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerConfig.java b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerConfig.java
index f9f1624e22bd..7b2ac5f4d851 100644
--- a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerConfig.java
+++ b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerConfig.java
@@ -25,10 +25,11 @@
 import static io.airlift.configuration.testing.ConfigAssertions.assertFullMapping;
 import static io.airlift.configuration.testing.ConfigAssertions.assertRecordedDefaults;
 import static io.airlift.configuration.testing.ConfigAssertions.recordDefaults;
+import static java.util.Map.entry;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
-public class TestKafkaEventListenerConfig
+final class TestKafkaEventListenerConfig
 {
     @Test
     void testDefaults()
@@ -84,7 +85,7 @@ void testExplicitPropertyMappings()
     }
 
     @Test
-    public void testExcludedFields()
+    void testExcludedFields()
     {
         KafkaEventListenerConfig conf = new KafkaEventListenerConfig();
         // check default
@@ -94,53 +95,47 @@ public void testExcludedFields()
         // check setting multiple
         conf.setExcludedFields(Set.of("payload", "plan", "user", "groups"));
         excludedFields = conf.getExcludedFields();
-        assertThat(excludedFields.size()).isEqualTo(4);
-        assertThat(excludedFields.contains("payload")).isTrue();
-        assertThat(excludedFields.contains("plan")).isTrue();
-        assertThat(excludedFields.contains("user")).isTrue();
-        assertThat(excludedFields.contains("groups")).isTrue();
+        assertThat(excludedFields)
+                .containsOnly("payload", "plan", "user", "groups");
 
         // setting to empty
         conf.setExcludedFields(Set.of(""));
         excludedFields = conf.getExcludedFields();
-        assertThat(excludedFields.size()).isEqualTo(0);
+        assertThat(excludedFields).isEmpty();
 
         // setting to empty with commas
         conf.setExcludedFields(Set.of(" ", ""));
         excludedFields = conf.getExcludedFields();
-        assertThat(excludedFields.size()).isEqualTo(0);
+        assertThat(excludedFields).isEmpty();
     }
 
     @Test
-    public void testKafkaClientOverrides()
+    void testKafkaClientOverrides()
     {
         KafkaEventListenerConfig conf = new KafkaEventListenerConfig();
         // check default
         Map<String, String> overrides = conf.getKafkaClientOverrides();
-        assertThat(overrides.size()).isEqualTo(0);
+        assertThat(overrides).isEmpty();
 
         // check setting just one
         conf.setKafkaClientOverrides("buffer.memory=444555");
         overrides = conf.getKafkaClientOverrides();
-        assertThat(overrides.size()).isEqualTo(1);
-        assertThat(overrides.get("buffer.memory")).isEqualTo("444555");
+        assertThat(overrides).containsExactly(entry("buffer.memory", "444555"));
 
         // check setting multiple
         conf.setKafkaClientOverrides("buffer.memory=444555, compression.type=zstd");
         overrides = conf.getKafkaClientOverrides();
-        assertThat(overrides.size()).isEqualTo(2);
-        assertThat(overrides.get("buffer.memory")).isEqualTo("444555");
-        assertThat(overrides.get("compression.type")).isEqualTo("zstd");
+        assertThat(overrides)
+                .containsExactly(entry("buffer.memory", "444555"), entry("compression.type", "zstd"));
 
         // check empty trailing param
         conf.setKafkaClientOverrides("buffer.memory=555777,");
         overrides = conf.getKafkaClientOverrides();
-        assertThat(overrides.size()).isEqualTo(1);
-        assertThat(overrides.get("buffer.memory")).isEqualTo("555777");
+        assertThat(overrides).containsExactly(entry("buffer.memory", "555777"));
 
         conf.setKafkaClientOverrides(",, ,");
         overrides = conf.getKafkaClientOverrides();
-        assertThat(overrides.size()).isEqualTo(0);
+        assertThat(overrides).isEmpty();
 
         // check missing = throws
         assertThatThrownBy(() -> conf.setKafkaClientOverrides("invalid,buffer.memory=555777"))
diff --git a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerPlugin.java b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerPlugin.java
index 7bd55ecc705d..ec3e4551222f 100644
--- a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerPlugin.java
+++ b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaEventListenerPlugin.java
@@ -39,7 +39,7 @@
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static org.assertj.core.api.Assertions.assertThat;
 
-public class TestKafkaEventListenerPlugin
+final class TestKafkaEventListenerPlugin
 {
     private static final String CREATED_TOPIC = "query_created";
     private static final String COMPLETED_TOPIC = "query_completed";
diff --git a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaRecordBuilder.java b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaRecordBuilder.java
index 1d7d0e7eb19b..b8ac412959db 100644
--- a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaRecordBuilder.java
+++ b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestKafkaRecordBuilder.java
@@ -28,9 +28,10 @@
 import java.util.Map;
 import java.util.Set;
 
+import static java.util.Map.entry;
 import static org.assertj.core.api.Assertions.assertThat;
 
-public class TestKafkaRecordBuilder
+final class TestKafkaRecordBuilder
 {
     private static final ObjectMapper MAPPER = new ObjectMapper();
     private static final Set<String> EXCLUDED_FIELDS = ImmutableSet.of(
@@ -44,7 +45,7 @@ public class TestKafkaRecordBuilder
     private static final MetadataProvider TEST_PROVIDER = new TestMetadataProvider("TRINO_INSIGHTS");
 
     @Test
-    public void testBuildKafkaRecord()
+    void testBuildKafkaRecord()
             throws IOException
     {
         KafkaRecordBuilder builder = new KafkaRecordBuilder("TestQueryStartedEvent", "TestQueryCompletedEvent", EXCLUDED_FIELDS, TEST_PROVIDER);
@@ -60,7 +61,7 @@ public void testBuildKafkaRecord()
     }
 
     @Test
-    public void testBuildKafkaRecordWithExclusions()
+    void testBuildKafkaRecordWithExclusions()
             throws IOException
     {
         Set<String> exclude = Sets.union(EXCLUDED_FIELDS, Set.of("query", "principal", "analysisTime", "writtenBytes"));
@@ -81,7 +82,7 @@ public void testBuildKafkaRecordWithExclusions()
     }
 
     @Test
-    public void testBuildKafkaRecordWithMetadata()
+    void testBuildKafkaRecordWithMetadata()
             throws IOException
     {
         Set<String> exclude = Sets.union(EXCLUDED_FIELDS, Set.of("context", "payload", "analysisTime"));
@@ -94,8 +95,7 @@ public void testBuildKafkaRecordWithMetadata()
         assertThat(record.key()).isNull();
         Map<String, String> metadata = MAPPER.readValue(MAPPER.readTree(record.value()).get("eventMetadata").toString(), Map.class);
 
-        assertThat(metadata.size()).isEqualTo(1);
-        assertThat(metadata.get("baz")).isEqualTo("yoo");
+        assertThat(metadata).containsExactly(entry("baz", "yoo"));
     }
 
     static class TestMetadataProvider
diff --git a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestUtils.java b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestUtils.java
index a0df8f1d51b6..7c1f56cb6bb8 100644
--- a/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestUtils.java
+++ b/plugin/trino-kafka-event-listener/src/test/java/io/trino/plugin/eventlistener/kafka/TestUtils.java
@@ -46,7 +46,7 @@
 import static io.trino.spi.type.TimeZoneKey.UTC_KEY;
 import static java.time.Duration.ofMillis;
 
-public class TestUtils
+public final class TestUtils
 {
     private static final QueryIOMetadata queryIOMetadata;
     private static final QueryContext queryContext;