Remove Feign dependency

conjure-java-jaxrs-client/build.gradle

@@ -7,11 +7,6 @@ dependencies {
     api project(":client-config")
     api project(":conjure-java-legacy-clients")
     api "com.google.code.findbugs:jsr305"
-    // TODO(dsanduleac): Should be implementation, but can't because we expose feign.TextDelegateEncoder
-    api "com.netflix.feign:feign-core", {
-        // prefer jakarta.ws.rs:jakarta.ws.rs-api
-        exclude group: 'javax.ws.rs', module: 'javax.ws.rs-api'
-    }
     api "com.palantir.dialogue:dialogue-target"
 
     implementation project(":conjure-java-annotations")
@@ -35,11 +30,9 @@ dependencies {
     implementation project(":conjure-java-jackson-serialization")
     implementation "com.google.guava:guava"
     implementation "com.github.ben-manes.caffeine:caffeine"
-    implementation "com.netflix.feign:feign-jackson"
     testImplementation project(":conjure-java-jersey-jakarta-server")
     testImplementation project(':keystores')
     testImplementation project(':undertow-jakarta-testing')
-    testImplementation "com.netflix.feign:feign-jackson"
     testImplementation "com.squareup.okhttp3:mockwebserver"
     testImplementation "org.junit.jupiter:junit-jupiter"
     testImplementation 'org.junit.jupiter:junit-jupiter-api'
@@ -48,11 +41,3 @@ dependencies {
     testImplementation "org.mockito:mockito-junit-jupiter"
     testImplementation "com.palantir.safe-logging:preconditions-assertj"
 }
-
-// feign.DefaultMethodHandler sets Lookup.IMPL_LOOKUP accessible resulting in
-// InaccessibleObjectException: Unable to make field static final java.lang.invoke.MethodHandles$Lookup
-// java.lang.invoke.MethodHandles$Lookup.IMPL_LOOKUP accessible: module java.base does not
-// "opens java.lang.invoke" to unnamed module
-moduleJvmArgs {
-    opens 'java.base/java.lang.invoke'
-}

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/feignimpl/AbstractDelegatingContract.java → conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/AbstractDelegatingContract.java

@@ -1,5 +1,5 @@
 /*
- * (c) Copyright 2017 Palantir Technologies Inc. All rights reserved.
+ * (c) Copyright 2026 Palantir Technologies Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,19 +14,16 @@
  * limitations under the License.
  */
 
-package com.palantir.conjure.java.client.jaxrs.feignimpl;
+package com.palantir.conjure.java.client.jaxrs;
 
-import feign.Contract;
-import feign.Feign;
-import feign.MethodMetadata;
 import java.lang.reflect.Method;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
 /**
  * Base class that provides the structure for a delegating {@link Contract}. Delegates the initial
- * {@link #parseAndValidatateMetadata(Class)} call to the wrapped Contract and then calls {@link #processMetadata(Class,
+ * {@link #parseAndValidateMetadata(Class)} call to the wrapped Contract and then calls {@link #processMetadata(Class,
  * Method, MethodMetadata)} on all of the methods that have metadata from the initial call.
  */
 abstract class AbstractDelegatingContract implements Contract {
@@ -38,8 +35,8 @@ abstract class AbstractDelegatingContract implements Contract {
     }
 
     @Override
-    public final List<MethodMetadata> parseAndValidatateMetadata(Class<?> targetType) {
-        List<MethodMetadata> mdList = delegate.parseAndValidatateMetadata(targetType);
+    public final List<MethodMetadata> parseAndValidateMetadata(Class<?> targetType) {
+        List<MethodMetadata> mdList = delegate.parseAndValidateMetadata(targetType);
 
         Map<String, MethodMetadata> methodMetadataByConfigKey = new LinkedHashMap<String, MethodMetadata>();
         for (MethodMetadata md : mdList) {
@@ -60,5 +57,5 @@ public final List<MethodMetadata> parseAndValidatateMetadata(Class<?> targetType
         return mdList;
     }
 
-    protected abstract void processMetadata(Class<?> targetType, Method method, MethodMetadata metadata);
+    abstract void processMetadata(Class<?> targetType, Method method, MethodMetadata metadata);
 }

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/AbstractFeignJaxRsClientBuilder.java

@@ -21,21 +21,6 @@
 import com.palantir.conjure.java.annotations.JaxRsServer;
 import com.palantir.conjure.java.api.config.service.UserAgent;
 import com.palantir.conjure.java.client.config.ClientConfiguration;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.CborDelegateDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.CborDelegateEncoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.EmptyContainerDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.EndpointNameHeaderEnrichmentContract;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.GuavaOptionalAwareContract;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.GuavaOptionalAwareDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.InputStreamDelegateDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.InputStreamDelegateEncoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.Java8OptionalAwareContract;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.Java8OptionalAwareDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.MethodHeaderEnrichmentContract;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.NeverReturnNullDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.SlashEncodingContract;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.TextDelegateDecoder;
-import com.palantir.conjure.java.client.jaxrs.feignimpl.TextDelegateEncoder;
 import com.palantir.conjure.java.dialogue.serde.DefaultConjureRuntime;
 import com.palantir.conjure.java.okhttp.HostEventsSink;
 import com.palantir.dialogue.Channel;
@@ -46,17 +31,6 @@
 import com.palantir.logsafe.Safe;
 import com.palantir.logsafe.SafeArg;
 import com.palantir.logsafe.exceptions.SafeIllegalArgumentException;
-import feign.Contract;
-import feign.Feign;
-import feign.Logger;
-import feign.Request;
-import feign.RequestTemplate;
-import feign.Retryer;
-import feign.Target;
-import feign.codec.Decoder;
-import feign.codec.Encoder;
-import feign.jackson.JacksonDecoder;
-import java.util.Objects;
 
 /** Not meant to be implemented outside of this library. */
 abstract class AbstractFeignJaxRsClientBuilder {
@@ -72,9 +46,9 @@ abstract class AbstractFeignJaxRsClientBuilder {
         this.config = config;
     }
 
-    protected abstract ObjectMapper getObjectMapper();
+    abstract ObjectMapper getObjectMapper();
 
-    protected abstract ObjectMapper getCborObjectMapper();
+    abstract ObjectMapper getCborObjectMapper();
 
     /** Set the host metrics registry to use when constructing the OkHttp client. */
     final AbstractFeignJaxRsClientBuilder hostEventsSink(HostEventsSink newHostEventsSink) {
@@ -116,8 +90,6 @@ static <T> T create(
                 .decoder(createDecoder(clientNameForLogging, jsonMapper, cborMapper))
                 .errorDecoder(new DialogueFeignClient.RemoteExceptionDecoder(runtime))
                 .client(new DialogueFeignClient(serviceClass, channel, runtime, FeignDialogueTarget.BASE_URL))
-                .logLevel(Logger.Level.NONE) // we use Dialogue for logging. (note that NONE is the default)
-                .retryer(new Retryer.Default(0, 0, 1)) // use dialogue retry mechanism only
                 .target(new FeignDialogueTarget<>(serviceClass, channel));
     }
 
@@ -126,57 +98,25 @@ static <T> T create(
      * target. However, there's a great deal of other configuration, and we handle failover/retries in Dialogue
      * which makes every client appear to use the same URL.
      */
-    private static final class FeignDialogueTarget<T> implements Target<T> {
+    private record FeignDialogueTarget<T>(Class<T> serviceClass, Channel channel) implements Target<T> {
         private static final String BASE_URL = "dialogue://feign";
 
-        private final Class<T> serviceClass;
-        private final Target<T> delegate;
-        // For equality checks
-        private final Channel channel;
-
-        FeignDialogueTarget(Class<T> serviceClass, Channel channel) {
-            this.serviceClass = serviceClass;
-            this.channel = channel;
-            this.delegate = new HardCodedTarget<>(serviceClass, BASE_URL);
-        }
-
         @Override
         public Class<T> type() {
             return serviceClass;
         }
 
-        @Override
-        public String name() {
-            return delegate.name();
-        }
-
         @Override
         public String url() {
-            return delegate.url();
+            return BASE_URL;
         }
 
         @Override
         public Request apply(RequestTemplate input) {
-            return delegate.apply(input);
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (this == other) {
-                return true;
-            }
-            if (other == null || getClass() != other.getClass()) {
-                return false;
+            if (input.url().indexOf("http") != 0) {
+                input.insert(0, url());
             }
-            FeignDialogueTarget<?> that = (FeignDialogueTarget<?>) other;
-            return serviceClass.equals(that.serviceClass)
-                    && delegate.equals(that.delegate)
-                    && channel.equals(that.channel);
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(serviceClass, delegate, channel);
+            return input.request();
         }
     }
 
@@ -205,7 +145,7 @@ private static Decoder createDecoder(
 
     private static Encoder createEncoder(
             @Safe String clientNameForLogging, ObjectMapper jsonMapper, ObjectMapper cborMapper) {
-        Encoder encoder = new ConjureFeignJacksonEncoder(jsonMapper);
+        Encoder encoder = new JacksonEncoder(jsonMapper);
         encoder = new CborDelegateEncoder(cborMapper, encoder);
         encoder = new TextDelegateEncoder(encoder);
         encoder = new InputStreamDelegateEncoder(clientNameForLogging, encoder);

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/feignimpl/CborDelegateDecoder.java → conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/CborDelegateDecoder.java

@@ -1,5 +1,5 @@
 /*
- * (c) Copyright 2019 Palantir Technologies Inc. All rights reserved.
+ * (c) Copyright 2026 Palantir Technologies Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,15 +14,12 @@
  * limitations under the License.
  */
 
-package com.palantir.conjure.java.client.jaxrs.feignimpl;
+package com.palantir.conjure.java.client.jaxrs;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.net.HttpHeaders;
-import feign.FeignException;
-import feign.Response;
-import feign.codec.Decoder;
 import java.io.IOException;
 import java.io.PushbackInputStream;
 import java.lang.reflect.Type;
@@ -37,18 +34,18 @@
  * <p>Ideally we'll codegen a client which handles the content-type switching where necessary (multiple possible
  * response Content-Types from the server) and does not do the checking where this is known at compile time.
  */
-public final class CborDelegateDecoder implements Decoder {
+final class CborDelegateDecoder implements Decoder {
 
     private final ObjectMapper cborMapper;
     private final Decoder delegate;
 
-    public CborDelegateDecoder(ObjectMapper cborMapper, Decoder delegate) {
+    CborDelegateDecoder(ObjectMapper cborMapper, Decoder delegate) {
         this.cborMapper = cborMapper;
         this.delegate = delegate;
     }
 
     @Override
-    public Object decode(Response response, Type type) throws IOException, FeignException {
+    public Object decode(Response response, Type type) throws IOException {
         Collection<String> contentTypes =
                 HeaderAccessUtils.caseInsensitiveGet(response.headers(), HttpHeaders.CONTENT_TYPE);
         if (contentTypes == null) {

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/feignimpl/CborDelegateEncoder.java → conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/CborDelegateEncoder.java

@@ -1,5 +1,5 @@
 /*
- * (c) Copyright 2019 Palantir Technologies Inc. All rights reserved.
+ * (c) Copyright 2026 Palantir Technologies Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,19 +14,15 @@
  * limitations under the License.
  */
 
-package com.palantir.conjure.java.client.jaxrs.feignimpl;
+package com.palantir.conjure.java.client.jaxrs;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.net.HttpHeaders;
-import feign.RequestTemplate;
-import feign.codec.EncodeException;
-import feign.codec.Encoder;
 import java.io.UncheckedIOException;
 import java.lang.reflect.Type;
-import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 
 /**
@@ -38,20 +34,20 @@
  * <p>In the future we will likely codegen the client and thus remove the need for scanning the headers on every
  * request.
  */
-public final class CborDelegateEncoder implements Encoder {
+final class CborDelegateEncoder implements Encoder {
 
     public static final String MIME_TYPE = "application/cbor";
 
     private final ObjectMapper cborMapper;
     private final Encoder delegate;
 
-    public CborDelegateEncoder(ObjectMapper cborMapper, Encoder delegate) {
+    CborDelegateEncoder(ObjectMapper cborMapper, Encoder delegate) {
         this.cborMapper = cborMapper;
         this.delegate = delegate;
     }
 
     @Override
-    public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException {
+    public void encode(Object object, Type bodyType, RequestTemplate template) {
         Collection<String> contentTypes =
                 HeaderAccessUtils.caseInsensitiveGet(template.headers(), HttpHeaders.CONTENT_TYPE);
         if (contentTypes == null) {
@@ -65,7 +61,7 @@ public void encode(Object object, Type bodyType, RequestTemplate template) throw
 
         try {
             JavaType javaType = cborMapper.getTypeFactory().constructType(bodyType);
-            template.body(cborMapper.writerFor(javaType).writeValueAsBytes(object), StandardCharsets.UTF_8);
+            template.body(cborMapper.writerFor(javaType).writeValueAsBytes(object));
         } catch (JsonProcessingException e) {
             throw new UncheckedIOException(e);
         }

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/Client.java

@@ -0,0 +1,33 @@
+/*
+ * (c) Copyright 2026 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.palantir.conjure.java.client.jaxrs;
+
+import java.io.IOException;
+
+/**
+ * Submits HTTP {@link Request requests}. Implementations are expected to be thread-safe.
+ */
+interface Client {
+
+    /**
+     * Executes a request against its {@link Request#url() url} and returns a response.
+     *
+     * @param request safe to replay.
+     * @return connected response, {@link Response.Body} is absent or unread
+     * @throws IOException on a network error connecting to {@link Request#url()}.
+     */
+    Response execute(Request request) throws IOException;
+}

conjure-java-jaxrs-client/src/main/java/com/palantir/conjure/java/client/jaxrs/CompatibleJaxRsContract.java

@@ -21,8 +21,6 @@
 import com.palantir.logsafe.Preconditions;
 import com.palantir.logsafe.SafeArg;
 import com.palantir.logsafe.exceptions.SafeIllegalStateException;
-import feign.Contract;
-import feign.MethodMetadata;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Method;
 import java.util.Collection;
@@ -34,10 +32,10 @@
  * JAXRSContract.java</a> which is licensed under Apache 2.
  * We have modified the implementation to handle both jaxrs and jakarta annotations, easing migrations.
  */
-public final class CompatibleJaxRsContract extends Contract.BaseContract {
+final class CompatibleJaxRsContract extends Contract.BaseContract {
 
     @Override
-    protected void processAnnotationOnClass(MethodMetadata data, Class<?> clz) {
+    void processAnnotationOnClass(MethodMetadata data, Class<?> clz) {
         Annotation path = Annotations.PATH.getAnnotation(clz);
         if (path != null) {
             String pathValue = Strings.emptyToNull(getAnnotationValue(path));
@@ -63,7 +61,7 @@ protected void processAnnotationOnClass(MethodMetadata data, Class<?> clz) {
     }
 
     @Override
-    protected void processAnnotationOnMethod(MethodMetadata data, Annotation methodAnnotation, Method method) {
+    void processAnnotationOnMethod(MethodMetadata data, Annotation methodAnnotation, Method method) {
         Class<? extends Annotation> annotationType = methodAnnotation.annotationType();
         Annotation http = Annotations.HTTP_METHOD.getAnnotation(annotationType);
         if (http != null) {
@@ -112,7 +110,7 @@ private void handleConsumesAnnotation(MethodMetadata data, Annotation consumes,
     }
 
     @Override
-    protected boolean processAnnotationsOnParameter(MethodMetadata data, Annotation[] annotations, int paramIndex) {
+    boolean processAnnotationsOnParameter(MethodMetadata data, Annotation[] annotations, int paramIndex) {
         boolean isHttpParam = false;
         for (Annotation parameterAnnotation : annotations) {
             Class<? extends Annotation> annotationType =