diff --git a/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportStartDatafeedAction.java b/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportStartDatafeedAction.java
index 9ba53c6e0b7..63fb9964eda 100644
--- a/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportStartDatafeedAction.java
+++ b/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportStartDatafeedAction.java
@@ -121,7 +121,7 @@ public class TransportStartDatafeedAction extends TransportMasterNodeAction<Star
                 @Override
                 public void onFailure(Exception e) {
                     if (e instanceof ResourceAlreadyExistsException) {
-                        logger.debug(e);
+                        logger.debug("datafeed already started", e);
                         e = new ElasticsearchStatusException("cannot start datafeed [" + params.getDatafeedId() +
                                 "] because it has already been started", RestStatus.CONFLICT);
                     }
diff --git a/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/TokenService.java b/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/TokenService.java
index 49f9b9c01a9..a193cce3acd 100644
--- a/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/TokenService.java
+++ b/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/TokenService.java
@@ -1392,7 +1392,7 @@ public final class TokenService extends AbstractComponent {
                 try {
                     refreshMetaData(custom);
                 } catch (Exception e) {
-                    logger.warn(e);
+                    logger.warn("refreshing metadata failed", e);
                 }
                 logger.info("refreshed keys");
             }
diff --git a/plugin/sql/sql-proto/build.gradle b/plugin/sql/sql-proto/build.gradle
index 9ee55f57df2..7be5f50ffac 100644
--- a/plugin/sql/sql-proto/build.gradle
+++ b/plugin/sql/sql-proto/build.gradle
@@ -5,6 +5,8 @@
  * be called "proto" there.
  */
 
+import org.elasticsearch.gradle.precommit.PrecommitTasks
+
 apply plugin: 'elasticsearch.build'
 
 description = 'Request and response objects shared by the cli, jdbc ' +
@@ -29,6 +31,11 @@ dependencies {
     testCompile "org.elasticsearch.test:framework:${version}"
 }
 
+forbiddenApisMain {
+    //sql does not depend on server, so only jdk signatures should be checked
+    signaturesURLs = [PrecommitTasks.getResource('/forbidden/jdk-signatures.txt')]
+}
+
 dependencyLicenses {
     mapping from: /elasticsearch-core.*/, to: 'elasticsearch'
     mapping from: /jackson-.*/, to: 'jackson'