Remove animal sniffer from low-level REST client (#29646)

The low-level REST client targets JDK 7. To avoid compiling against JDK
functionality not available in JDK 7, we use animal sniffer. However,
when we switched to using the JDK 9 and now the JDK 10 compiler which
has built-in support for targeting previous JDKs, we no longer need to
use animal sniffer. This is because the JDK is now packaged with the
signatures needed to ensure that when we target JDK 7 at compile-time it
is detected that we are only using JDK 7 functionality. This commit
removes the use of animal sniffer from the low-level REST client build.

client/rest/build.gradle

@@ -20,7 +20,6 @@
 import org.elasticsearch.gradle.precommit.PrecommitTasks
 
 apply plugin: 'elasticsearch.build'
-apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'nebula.maven-base-publish'
 apply plugin: 'nebula.maven-scm'
 
@@ -52,8 +51,6 @@ dependencies {
   testCompile "org.hamcrest:hamcrest-all:${versions.hamcrest}"
   testCompile "org.elasticsearch:securemock:${versions.securemock}"
   testCompile "org.elasticsearch:mocksocket:${versions.mocksocket}"
-  testCompile "org.codehaus.mojo:animal-sniffer-annotations:1.15"
-  signature "org.codehaus.mojo.signature:java17:1.0@signature"
 }
 
 forbiddenApisMain {

client/rest/src/test/java/org/elasticsearch/client/RestClientBuilderIntegTests.java

@@ -24,7 +24,6 @@ import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpsConfigurator;
 import com.sun.net.httpserver.HttpsServer;
 import org.apache.http.HttpHost;
-import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 import org.elasticsearch.mocksocket.MockHttpServer;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -46,8 +45,6 @@ import static org.junit.Assert.fail;
 /**
  * Integration test to validate the builder builds a client with the correct configuration
  */
-//animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-@IgnoreJRERequirement
 public class RestClientBuilderIntegTests extends RestClientTestCase {
 
     private static HttpsServer httpsServer;
@@ -60,8 +57,6 @@ public class RestClientBuilderIntegTests extends RestClientTestCase {
         httpsServer.start();
     }
 
-    //animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-    @IgnoreJRERequirement
     private static class ResponseHandler implements HttpHandler {
         @Override
         public void handle(HttpExchange httpExchange) throws IOException {

client/rest/src/test/java/org/elasticsearch/client/RestClientMultipleHostsIntegTests.java

@@ -23,7 +23,6 @@ import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
 import org.apache.http.HttpHost;
-import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 import org.elasticsearch.mocksocket.MockHttpServer;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -48,8 +47,6 @@ import static org.junit.Assert.assertTrue;
  * Integration test to check interaction between {@link RestClient} and {@link org.apache.http.client.HttpClient}.
  * Works against real http servers, multiple hosts. Also tests failover by randomly shutting down hosts.
  */
-//animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-@IgnoreJRERequirement
 public class RestClientMultipleHostsIntegTests extends RestClientTestCase {
 
     private static HttpServer[] httpServers;
@@ -90,8 +87,6 @@ public class RestClientMultipleHostsIntegTests extends RestClientTestCase {
         return httpServer;
     }
 
-    //animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-    @IgnoreJRERequirement
     private static class ResponseHandler implements HttpHandler {
         private final int statusCode;
 

client/rest/src/test/java/org/elasticsearch/client/RestClientSingleHostIntegTests.java

@@ -33,7 +33,6 @@ import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
 import org.apache.http.util.EntityUtils;
-import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 import org.elasticsearch.mocksocket.MockHttpServer;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -64,8 +63,6 @@ import static org.junit.Assert.fail;
  * Integration test to check interaction between {@link RestClient} and {@link org.apache.http.client.HttpClient}.
  * Works against a real http server, one single host.
  */
-//animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-@IgnoreJRERequirement
 public class RestClientSingleHostIntegTests extends RestClientTestCase {
 
     private static HttpServer httpServer;
@@ -91,8 +88,6 @@ public class RestClientSingleHostIntegTests extends RestClientTestCase {
         return httpServer;
     }
 
-    //animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-    @IgnoreJRERequirement
     private static class ResponseHandler implements HttpHandler {
         private final int statusCode;