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/*
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*
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package org.graalvm.nativeimage;
import org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport;
/**
* This class provides methods that can be called during native image building to configure class
* initialization behavior. By default, all classes that are seen as reachable for a native image
* are initialized during image building, i.e., the class initialization method is executed during
* image building and is not seen as a reachable method at runtime. But for some classes, it is
* necessary to execute the class initialization method at runtime, e.g., when the class
* initialization method loads shared libraries ({@code System.loadLibrary}), allocates native
* memory ({@code ByteBuffer.allocateDirect}), or starts threads.
*
* This class provides two different registration methods: Classes registered via
* {@link #delayClassInitialization} are not initialized at all during image generation, and only
* initialized at runtime, i.e., the class initializer is executed once at runtime. Classes
* registered via {@link RuntimeClassInitialization#rerunClassInitialization} are initialized during
* image generation, and again initialized at runtime, i.e., the class initializer is executed
* twice.
*
* Registering a class automatically registers all subclasses too. It would violate the class
* initialization specification to have an uninitialized class that has an initialized subclass.
*
* Initializing classes at runtime comes with some costs and restrictions:
*
* - The class initialization status must be checked before a static field access, static method
* call, and object allocation of such classes. This has an impact on performance.
* - Instances of such classes are not allowed on the image heap, i.e., on the initial heap that
* is part of the native executable. Otherwise instances would exist before the class is
* initialized, which violates the class initialization specification.
*
*
* @since 1.0
*/
@Platforms(Platform.HOSTED_ONLY.class)
public final class RuntimeClassInitialization {
/**
* Registers the provided classes, and all of their subclasses, for class initialization at
* runtime. The classes are not initialized automatically during image generation, and also must
* not be initialized manually by the user during image generation.
*
* Unfortunately, classes are initialized for many reasons, and it is not possible to intercept
* class initialization and report an error at this time. If a registered class gets
* initialized, an error can be reported only later and the user must manually debug the reason
* for class initialization. This can be done by, e.g., setting a breakpoint in the class
* initializer or adding debug printing (print the stack trace) in the class initializer.
*
* @since 1.0
*/
public static void delayClassInitialization(Class... classes) {
ImageSingletons.lookup(RuntimeClassInitializationSupport.class).delayClassInitialization(classes);
}
/**
* Registers the provided classes, and all of their subclasses, for class re-initialization at
* runtime. The classes are still initialized during image generation, i.e., the class
* initializers run twice.
*
* Static fields of the registered classes start out with their default values at runtime, i.e.,
* values assigned by class initializers (or for any other reason) to static fields are not
* available at runtime.
*
* It is up to the user to ensure that this behavior makes sense and does not lead to wrong
* application behavior.
*
*
* @since 1.0
*/
public static void rerunClassInitialization(Class... classes) {
ImageSingletons.lookup(RuntimeClassInitializationSupport.class).rerunClassInitialization(classes);
}
private RuntimeClassInitialization() {
}
}