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Native Image Options

The native-image builder needs to provide the classpath for all classes using the familiar option from the java launcher: -cp is followed by a list of directories or JAR files, separated by :. The name of the class containing the main method is the last argument, or you can use -jar and provide a JAR file that specifies the main method in its manifest.

The syntax of the native-image command is:

• native-image [options] class [imagename] [options] to build an executable file for a class in the current working directory. Invoking it executes the native-compiled code of that class.

• native-image [options] -jar jarfile [imagename] [options] to build an image for a JAR file.

The options passed to native-image are evaluated left-to-right. For more information, see Native Image Build Configuration.

The options fall into four categories: image generation options, macro options, non-standard options, and server options. Non-standard and server options are subject to change through a deprecation cycle.

Command-line help is available. Run native-image --help to get the commands overview, and native-image --help-extra to print help on non-standard, macro, and server options.

Options to Native Image Builder #

Depending on the GraalVM edition, the options to the native image builder (native-image) may differ. The following options are equally supported with both GraalVM Communty and Enterprise editions:

• -cp, -classpath, --class-path <class search path of directories and zip/jar files>: a colon separated list of directories, JAR archives, and ZIP archives to search for class files.
• -D<name>=<value>: set a system property.
• -J<flag>: pass <flag> directly to the JVM running the native image builder.
• -O<level>: 0 for no optimizations, or 1 for basic optimizations (default).
• --verbose: enable verbose output.
• --version: print the product version and exit.
• --help: print this help message.
• --help-extra: print help on non-standard options.
• --allow-incomplete-classpath: allow the image build with an incomplete class path. Report type resolution errors at runtime when they are accessed the first time, instead of during the image build.
• --auto-fallback: build a standalone image if possible.
• --enable-http: enable http support in a generated image.
• --enable-https: enable https support in a generated image.
• --enable-url-protocols: list comma-separated URL protocols to enable.
• --features: a comma-separated list of fully qualified feature implementation classes.
• --force-fallback: force building of a fallback image.
• --initialize-at-build-time: a comma-separated list of packages and classes (and implicitly all of their superclasses) that are initialized during the image build. An empty string designates all packages.
• --initialize-at-run-time: a comma-separated list of packages and classes (and implicitly all of their subclasses) that must be initialized at runtime and not during the image build. An empty string is currently not supported.
• --install-exit-handlers: provide java.lang.Terminator exit handlers for executable images.
• --libc: select the libc native library implementation to use (available implementations are glibc and musl).
• --native-compiler-options: provide a custom C compiler option used to query code compilation.
• --native-compiler-path: provide a custom path to the C compiler used to query code compilation and linking.
• --native-image-info: show native toolchain information and image’s build settings.
• --no-fallback: build a standalone image or report a failure.
• --report-unsupported-elements-at-runtime: report the usage of unsupported methods and fields at runtime when they are accessed the first time, instead of an error during an image building.
• --shared: build a shared library.
• --static: build a statically-linked executable (requires libc and zlib static libraries).
• --target: select the native image compilation target (in - format). It defaults to the host's OS-architecture pair.
• --trace-class-initialization: provide a comma-separated list of fully-qualified class names that a class initialization is traced for.
• --trace-object-instantiation: provide a comma-separated list of fully-qualified class names that an object instantiation is traced for.
• -da: disable assertions with specified granularity in the generated image. The -da[:[packagename]|:[classname] or -disableassertions[:[packagename]|:[classname] variants are also supported.
• -dsa: disable assertions in all system classes.
• -ea: enable assertions with specified granularity in a generated image. The -ea[:[packagename]|:[classname] or -enableassertions[:[packagename]|:[classname] variants are also supported.
• -esa: enable assertions in all system classes.

• -g: generate debugging information. Please be informed that debug information produced on GraalVM Community will differ from that generated on GraalVM Enterprise.

• GraalVM Enterprise only: --gc=<value>: select the Native Image garbage collector implementation. Allowed options for <value> are G1 for G1 garbage collector or serial for Serial garbage collector (default).
• GraalVM Enterprise only: --pgo: a comma-separated list of files from which to read the data collected for profile-guided optimization of AOT compiled code (reads from default.iprof if nothing is specified).
• GraalVM Enterprise only: --pgo-instrument: instrument AOT compiled code to collect data for profile-guided optimization into the default.iprof file.

Macro Options #

• --language:nfi: make the Truffle Native Function Interface language available
• --language:python: make Python available as a language for the image
• --language:R: make R available as a language for the image
• --language:regex: make the Truffle Regular Expression engine available
• --language:wasm: make WebAssembly available as a language for the image
• --language:llvm: make LLVM bitcode available as a language for the image
• --language:js: make JavaScript available as a language for the image
• --language:ruby: make Ruby available as a language for the image
• --tool:coverage: add source code coverage support to a GraalVM supported language
• --tool:insight: add support for detailed access to a program’s runtime behavior, allowing users to inspect values and types at invocation or allocation sites
• --tool:dap: add support to allow image to open a debugger port serving the Debug Adapter Protocol in IDEs like VS Code
• --tool:chromeinspector: add debugging support to a GraalVM supported language
• --tool:lsp: add the Language Server Protocol support to later attach compatible debuggers to GraalVM in IDEs like VS Code
• --tool:profiler: add profiling support to a GraalVM supported language

The --language:python, --language:ruby and --language:R polyglot macro options become available once the corresponding languages are added to the base GraalVM installation (see the GraalVM Updater guide).

Non-standard Options #

• --expert-options: list image build options for experts
• --expert-options-all : list all image build options for experts (use at your own risk)
• --expert-options-detail: display all available help for a comma-separated list of option names. Pass * to show extra help for all options that contain it
• --configurations-path <search path of option-configuration directories>: a separated list of directories to be treated as option-configuration directories
• --debug-attach[=< port >]: attach to debugger during image building (default port is 8000)
• --dry-run: output the command line that would be used for building
• -V<key>=<value>: provide values for placeholders in native-image.properties files
• --help-experimental-build-server: display help for the image-build server specific options

Native Image options are also distinguished as hosted and runtime options. Continue reading to the Native Image Hosted and Runtime Options guide.