@@ -76,3 +76,8 @@ release.properties
 pom.xml.releaseBackup
 .mvn/.develocity/develocity-workspace-id
 .sdkmanrc
+
+# AI assistant tooling
+.antigravitycli/
+.claude/
+.understand-anything/
@@ -44,7 +44,7 @@
 
     <dependency>
       <groupId>com.squareup.okhttp3</groupId>
-      <artifactId>mockwebserver</artifactId>
+      <artifactId>mockwebserver3</artifactId>
       <scope>test</scope>
     </dependency>
     <dependency>
 
@@ -45,7 +45,7 @@
 
     <dependency>
       <groupId>com.squareup.okhttp3</groupId>
-      <artifactId>mockwebserver</artifactId>
+      <artifactId>mockwebserver3</artifactId>
       <scope>test</scope>
     </dependency>
 
 
@@ -67,7 +67,7 @@ public final class StreamDecoder implements Decoder {
   @Override
   public Object decode(Response response, Type type) throws IOException, FeignException {
     if (!isStream(type)) {
-      if (!delegateDecoder.isPresent()) {
+      if (delegateDecoder.isEmpty()) {
         throw new IllegalArgumentException(
             "StreamDecoder supports types other than stream. "
                 + "When type is not stream, the delegate decoder needs to be setting.");
 
@@ -16,7 +16,7 @@
 package feign;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 import feign.Request.HttpMethod;
 import feign.Target.EmptyTarget;
@@ -33,24 +33,25 @@ void whenNameNotSupplied() {
 
   @Test
   void toString_withoutName() {
-    assertThat(EmptyTarget.create(UriInterface.class).toString())
-        .isEqualTo("EmptyTarget(type=UriInterface)");
+    assertThat(EmptyTarget.create(UriInterface.class))
+        .hasToString("EmptyTarget(type=UriInterface)");
   }
 
   @Test
   void toString_withName() {
-    assertThat(EmptyTarget.create(UriInterface.class, "manager-access").toString())
-        .isEqualTo("EmptyTarget(type=UriInterface, name=manager-access)");
+    assertThat(EmptyTarget.create(UriInterface.class, "manager-access"))
+        .hasToString("EmptyTarget(type=UriInterface, name=manager-access)");
   }
 
   @Test
   void mustApplyToAbsoluteUrl() {
     UnsupportedOperationException exception =
-        assertThrows(
-            UnsupportedOperationException.class,
-            () ->
-                EmptyTarget.create(UriInterface.class)
-                    .apply(new RequestTemplate().method(HttpMethod.GET).uri("/relative")));
+        assertThatExceptionOfType(UnsupportedOperationException.class)
+            .isThrownBy(
+                () ->
+                    EmptyTarget.create(UriInterface.class)
+                        .apply(new RequestTemplate().method(HttpMethod.GET).uri("/relative")))
+            .actual();
     assertThat(exception.getMessage())
         .isEqualTo("Request with non-absolute URL not supported with empty target");
   }
 
@@ -20,12 +20,14 @@
 
 import feign.Request.ProtocolVersion;
 import java.util.Arrays;
+import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
 public class EnumForNameTest {
 
-  public static class KnownEnumValuesTest {
+  @Nested
+  public class KnownEnumValuesTest {
     public Object name;
     public ProtocolVersion expectedProtocolVersion;
 
@@ -56,7 +58,8 @@ public void initKnownEnumValues(Object name, ProtocolVersion expectedProtocolVer
     }
   }
 
-  public static class UnknownEnumValuesTest {
+  @Nested
+  public class UnknownEnumValuesTest {
 
     public Object name;
 
 
@@ -16,7 +16,7 @@
 package feign;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -255,40 +255,41 @@ void lengthOfBodyExceptionTest() {
 
   @Test
   void nullRequestShouldThrowNPEwThrowable() {
-    assertThrows(
-        NullPointerException.class, () -> new Derived(404, "message", null, new Throwable()));
+    assertThatThrownBy(() -> new Derived(404, "message", null, new Throwable()))
+        .isInstanceOf(NullPointerException.class);
   }
 
   @Test
   void nullRequestShouldThrowNPEwThrowableAndBytes() {
-    assertThrows(
-        NullPointerException.class,
-        () ->
-            new Derived(
-                404,
-                "message",
-                null,
-                new Throwable(),
-                "content".getBytes(StandardCharsets.UTF_8),
-                Collections.emptyMap()));
+    assertThatThrownBy(
+            () ->
+                new Derived(
+                    404,
+                    "message",
+                    null,
+                    new Throwable(),
+                    "content".getBytes(StandardCharsets.UTF_8),
+                    Collections.emptyMap()))
+        .isInstanceOf(NullPointerException.class);
   }
 
   @Test
   void nullRequestShouldThrowNPE() {
-    assertThrows(NullPointerException.class, () -> new Derived(404, "message", null));
+    assertThatThrownBy(() -> new Derived(404, "message", null))
+        .isInstanceOf(NullPointerException.class);
   }
 
   @Test
   void nullRequestShouldThrowNPEwBytes() {
-    assertThrows(
-        NullPointerException.class,
-        () ->
-            new Derived(
-                404,
-                "message",
-                null,
-                "content".getBytes(StandardCharsets.UTF_8),
-                Collections.emptyMap()));
+    assertThatThrownBy(
+            () ->
+                new Derived(
+                    404,
+                    "message",
+                    null,
+                    "content".getBytes(StandardCharsets.UTF_8),
+                    Collections.emptyMap()))
+        .isInstanceOf(NullPointerException.class);
   }
 
   static class Derived extends FeignException {
 
@@ -23,7 +23,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class JavaLoggerTest {
+class JavaLoggerTest {
 
   private static final String CONFIG_KEY = "TestApi#testMethod()";
   private java.util.logging.Logger julLogger;
 
@@ -21,11 +21,10 @@
 import static org.mockito.Mockito.verify;
 
 import feign.Logger.Level;
-import java.io.IOException;
 import java.util.Collections;
 import org.junit.jupiter.api.Test;
 
-public class LoggerMethodsTest {
+class LoggerMethodsTest {
 
   Logger logger =
       new Logger() {
@@ -34,7 +33,7 @@ protected void log(String configKey, String format, Object... args) {}
       };
 
   @Test
-  void responseIsClosedAfterRebuffer() throws IOException {
+  void responseIsClosedAfterRebuffer() throws Exception {
     Request request =
         Request.create(Request.HttpMethod.GET, "/api", Collections.emptyMap(), null, null);
     Response response =
 
@@ -15,16 +15,14 @@
  */
 package feign;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import feign.Request.HttpMethod;
 import java.util.Collection;
 import java.util.Collections;
 import org.junit.jupiter.api.Test;
 
-public class LoggerRebufferTest {
+class LoggerRebufferTest {
 
   private static final String CONFIG_KEY = "TestApi#testMethod()";
 
@@ -55,8 +53,10 @@ void headersLevelRebuffersResponseBody() throws Exception {
     // then
     String read1 = Util.toString(result.body().asReader(Util.UTF_8));
     String read2 = Util.toString(result.body().asReader(Util.UTF_8));
-    assertEquals(originalBody, read1, "First read should return original body");
-    assertEquals(originalBody, read2, "Second read should return same body (rebuffered)");
+    assertThat(read1).as("First read should return original body").isEqualTo(originalBody);
+    assertThat(read2)
+        .as("Second read should return same body (rebuffered)")
+        .isEqualTo(originalBody);
   }
 
   @Test
@@ -79,7 +79,7 @@ void basicLevelDoesNotRebufferResponseBody() throws Exception {
 
     // then
     String read1 = Util.toString(result.body().asReader(Util.UTF_8));
-    assertEquals(originalBody, read1, "First read should return original body");
+    assertThat(read1).as("First read should return original body").isEqualTo(originalBody);
   }
 
   @Test
@@ -104,9 +104,9 @@ void fullLevelRebuffersResponseBody() throws Exception {
     String read1 = Util.toString(result.body().asReader(Util.UTF_8));
     String read2 = Util.toString(result.body().asReader(Util.UTF_8));
     String read3 = Util.toString(result.body().asReader(Util.UTF_8));
-    assertEquals(originalBody, read1, "First read should return original body");
-    assertEquals(originalBody, read2, "Second read should return same body");
-    assertEquals(originalBody, read3, "Third read should return same body");
+    assertThat(read1).as("First read should return original body").isEqualTo(originalBody);
+    assertThat(read2).as("Second read should return same body").isEqualTo(originalBody);
+    assertThat(read3).as("Third read should return same body").isEqualTo(originalBody);
   }
 
   @Test
@@ -129,7 +129,7 @@ void noneLevelDoesNotRebufferResponseBody() throws Exception {
 
     // then
     String read1 = Util.toString(result.body().asReader(Util.UTF_8));
-    assertEquals(originalBody, read1, "Body should be readable");
+    assertThat(read1).as("Body should be readable").isEqualTo(originalBody);
   }
 
   @Test
@@ -152,7 +152,7 @@ void http204DoesNotRebufferEvenAtHeadersLevel() throws Exception {
         logger.logAndRebufferResponse(CONFIG_KEY, Logger.Level.HEADERS, response, 100);
 
     // then
-    assertNotNull(result.body(), "Response body object should exist");
+    assertThat(result.body()).as("Response body object should exist").isNotNull();
   }
 
   @Test
@@ -174,7 +174,7 @@ void http205DoesNotRebufferEvenAtHeadersLevel() throws Exception {
         logger.logAndRebufferResponse(CONFIG_KEY, Logger.Level.HEADERS, response, 100);
 
     // then
-    assertNotNull(result.body(), "Response body object should exist");
+    assertThat(result.body()).as("Response body object should exist").isNotNull();
   }
 
   @Test
@@ -197,6 +197,6 @@ void nullBodyHandledCorrectlyAtHeadersLevel() throws Exception {
         logger.logAndRebufferResponse(CONFIG_KEY, Logger.Level.HEADERS, response, 100);
 
     // then
-    assertNull(result.body(), "Body should remain null");
+    assertThat(result.body()).as("Body should remain null").isNull();
   }
 }