diff --git a/docs/jvm_aot.md b/docs/jvm_aot.md new file mode 100644 index 0000000000..4eb682f54b --- /dev/null +++ b/docs/jvm_aot.md @@ -0,0 +1,18 @@ +# Ahead Of Time (AOT) compilation for the Java Virtual Machine (JVM)" + +Ahead Of Time (AOT) compilation build tools such as those provided by [GraalVM's `native-image`](https://www.graalvm.org/reference-manual/native-image/) can require some configuration when using protobuf. +Protobuf for the JVM uses reflection and some of its target classes are not possible to determine in advance. +Historically, there were good reasons to use reflection based on APIs that were published effectively requiring them, and this situation is unlikely to change. + +[The Lite version of protobuf for the JVM](https://github.com/protocolbuffers/protobuf/blob/master/java/lite.md) +avoids reflection and may be better suited for use with AOT compilation tooling. This Lite version was originally targeted for use on Android which has similar AOT compilation +goals as GraalVM's native-image tool. + +## GraalVM native-image + +This section addresses GraalVM's `native-image` configuration specifically as this AOT compilation tool due to its popularity. The `native-image` tool can be configured +with respect to: the [Java Native Interface](https://en.wikipedia.org/wiki/Java_Native_Interface) (JNI), http proxying, reflection, and other resources. While these +considerations can be manually declared as JSON files, we recommend that a JVM application is exercised along with +[the assisted configuration agent](https://www.graalvm.org/reference-manual/native-image/BuildConfiguration/#assisted-configuration-of-native-image-builds). The agent +will generate files that you can then subsequently point at when invoking `native-image`. We recommend that the generated files are retained with a project's source +code.