diff --git a/build.gradle b/build.gradle
index 46a0480..3656513 100644
--- a/build.gradle
+++ b/build.gradle
@@ -29,6 +29,10 @@ allprojects {
         }
     }
 
+    tasks.withType(JavaCompile).configureEach {
+        options.compilerArgs += ['-Werror']
+    }
+
     tasks.withType(Javadoc).configureEach {
         options.addBooleanOption "Xdoclint:-missing", true
         failOnError = false
diff --git a/okhttp-spring-client/build.gradle b/okhttp-spring-client/build.gradle
index d2f0eb7..ec7799d 100644
--- a/okhttp-spring-client/build.gradle
+++ b/okhttp-spring-client/build.gradle
@@ -12,4 +12,6 @@ dependencies {
 
     api "com.squareup.okhttp3:okhttp"
     api "org.springframework:spring-web"
+
+    compileOnly "com.google.code.findbugs:jsr305:3.0.2"
 }