diff --git a/core/deployment/src/main/java/io/quarkus/deployment/CodeGenProvider.java b/core/deployment/src/main/java/io/quarkus/deployment/CodeGenProvider.java
index 7974c580e6df0..04bdfbfb56d2d 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/CodeGenProvider.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/CodeGenProvider.java
@@ -16,9 +16,9 @@ public interface CodeGenProvider {
     String providerId();
 
     /**
-     * File extensions that CodeGenProvider will generate code from
+     * File extension that CodeGenProvider will generate code from
      *
-     * @return collection of file extensions
+     * @return file extension
      */
     @NotNull
     String inputExtension();
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/CodeGenerator.java b/core/deployment/src/main/java/io/quarkus/deployment/CodeGenerator.java
index 19472275f002e..5b7ce4af881fb 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/CodeGenerator.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/CodeGenerator.java
@@ -13,6 +13,9 @@
 import io.quarkus.bootstrap.prebuild.CodeGenException;
 import io.quarkus.deployment.codegen.CodeGenData;
 
+/**
+ * A set of methods to initialize and execute {@link CodeGenProvider}s.
+ */
 public class CodeGenerator {
 
     // used by Gradle
diff --git a/devtools/gradle/src/main/java/io/quarkus/gradle/tasks/QuarkusPrepare.java b/devtools/gradle/src/main/java/io/quarkus/gradle/tasks/QuarkusPrepare.java
index 0e8c61e573215..ec1c4fd1e01e1 100644
--- a/devtools/gradle/src/main/java/io/quarkus/gradle/tasks/QuarkusPrepare.java
+++ b/devtools/gradle/src/main/java/io/quarkus/gradle/tasks/QuarkusPrepare.java
@@ -33,7 +33,7 @@ public class QuarkusPrepare extends QuarkusTask {
     private boolean test = false;
 
     public QuarkusPrepare() {
-        super("Quarkus performs pre-build preparations, such as sources generation");
+        super("Performs Quarkus pre-build preparations, such as sources generation");
     }
 
     @TaskAction
diff --git a/devtools/maven/src/main/java/io/quarkus/maven/CodeGenMojo.java b/devtools/maven/src/main/java/io/quarkus/maven/CodeGenMojo.java
index 67f546f2171af..dc812e5b6131e 100644
--- a/devtools/maven/src/main/java/io/quarkus/maven/CodeGenMojo.java
+++ b/devtools/maven/src/main/java/io/quarkus/maven/CodeGenMojo.java
@@ -33,7 +33,7 @@
 import io.quarkus.deployment.CodeGenerator;
 import io.quarkus.deployment.codegen.CodeGenData;
 
-@Mojo(name = "prepare", defaultPhase = LifecyclePhase.GENERATE_SOURCES, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
+@Mojo(name = "prepare", defaultPhase = LifecyclePhase.GENERATE_SOURCES, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME, threadSafe = true)
 public class CodeGenMojo extends AbstractMojo {
 
     @Parameter(defaultValue = "${project.build.directory}")
diff --git a/docs/src/main/asciidoc/grpc-getting-started.adoc b/docs/src/main/asciidoc/grpc-getting-started.adoc
index ac4fb5ad7ff44..ae0ed1717d720 100644
--- a/docs/src/main/asciidoc/grpc-getting-started.adoc
+++ b/docs/src/main/asciidoc/grpc-getting-started.adoc
@@ -15,6 +15,16 @@ The default configuration is enough, but you can also select some extensions if
 
 == Configuring your project
 
+Edit the `pom.xml` file to add the Quarkus gRPC extension dependency (just under `<dependencies>`):
+
+[source,xml]
+----
+<dependency>
+  <groupId>io.quarkus</groupId>
+  <artifactId>quarkus-grpc</artifactId>
+</dependency>
+----
+
 Make sure you have `prepare` goal of `quarkus-maven-plugin` enabled in your `pom.xml`:
 
 [source,xml]
@@ -39,7 +49,7 @@ Make sure you have `prepare` goal of `quarkus-maven-plugin` enabled in your `pom
 
 With this configuration, you can put your service and message definitions in the `src/main/proto` directory.
 `quarkus-maven-plugin` will generate Java files from your `proto` files.
-Alternatively, you can use `protobuf-maven-plugin` to generate these files, more in <<Generating Java files from proto with protobuf-maven-plugin>>
+Alternatively to using the `prepare` goal of the `quarkus-maven-plugin`, you can use `protobuf-maven-plugin` to generate these files, more in <<Generating Java files from proto with protobuf-maven-plugin>>
 
 Let's start with a simple _Hello_ service.
 Create the `src/main/proto/helloworld.proto` file with the following content:
@@ -258,18 +268,9 @@ You can also package the application into a native executable with: `mvn package
 == Generating Java files from proto with protobuf-maven-plugin
 
 Alternatively to using Quarkus code generation to generate stubs for `proto` files, you can also use
-`protobuf-maven-plugin` for this purpose.
-To do it, edit the `pom.xml` file to add the quarkus gRPC extension dependency and the JSR 305 (just under `<dependencies>`):
-
-[source,xml]
-----
-<dependency>
-  <groupId>io.quarkus</groupId>
-  <artifactId>quarkus-grpc</artifactId>
-</dependency>
-----
+`protobuf-maven-plugin`.
 
-In the `<properties>` section, define the 2 following properties:
+To do it, first define the 2 following properties in the `<properties>` section:
 
 [source,xml,subs="verbatim,attributes"]
 ----
@@ -279,7 +280,7 @@ In the `<properties>` section, define the 2 following properties:
 
 They configure the gRPC version and the `protoc` version.
 
-Finally, add to the `build` section the `os-maven-plugin` extension and the `protobuf-maven-plugin` configuration.
+Then, add to the `build` section the `os-maven-plugin` extension and the `protobuf-maven-plugin` configuration.
 
 [source,xml,subs="verbatim,attributes"]
 ----