19 lines
1.6 KiB
Markdown
19 lines
1.6 KiB
Markdown
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# Ahead Of Time (AOT) compilation for the Java Virtual Machine (JVM)"
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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.
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Protobuf for the JVM uses reflection and some of its target classes are not possible to determine in advance.
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Historically, there were good reasons to use reflection based on APIs that were published effectively requiring them, and this situation is unlikely to change.
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[The Lite version of protobuf for the JVM](https://github.com/protocolbuffers/protobuf/blob/master/java/lite.md)
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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
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goals as GraalVM's native-image tool.
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## GraalVM native-image
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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
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with respect to: the [Java Native Interface](https://en.wikipedia.org/wiki/Java_Native_Interface) (JNI), http proxying, reflection, and other resources. While these
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considerations can be manually declared as JSON files, we recommend that a JVM application is exercised along with
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[the assisted configuration agent](https://www.graalvm.org/reference-manual/native-image/BuildConfiguration/#assisted-configuration-of-native-image-builds). The agent
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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
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code.
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