是否有可能找到Java本机方法的源代码？
我在Java中找到了Object的clone()方法：
protected native Object clone() throws CloneNotSupportedException;
该方法的来源是否可用？ 也许在OpenJDK ？
来自jdk / src / share / native / java / lang / Object.c
static JNINativeMethod methods[] = { {"hashCode", "()I", (void *)&JVM_IHashCode}, {"wait", "(J)V", (void *)&JVM_MonitorWait}, {"notify", "()V", (void *)&JVM_MonitorNotify}, {"notifyAll", "()V", (void *)&JVM_MonitorNotifyAll}, {"clone", "()Ljava/lang/Object;", (void *)&JVM_Clone}, };
这意味着它是一个函数指针（可能这样做，他们可以实现特定于平台的本机代码）
为JVM_Clone执行grep会产生以下因素：
（来自hotspot / src / share / vm / prims / jvm.cpp）
JVM_ENTRY(jobject, JVM_Clone(JNIEnv* env, jobject handle)) JVMWrapper("JVM_Clone"); Handle obj(THREAD, JNIHandles::resolve_non_null(handle)); const KlassHandle klass (THREAD, obj->klass()); JvmtiVMObjectAllocEventCollector oam; #ifdef ASSERT // Just checking that the cloneable flag is set correct if (obj->is_javaArray()) { guarantee(klass->is_cloneable(), "all arrays are cloneable"); } else { guarantee(obj->is_instance(), "should be instanceOop"); bool cloneable = klass->is_subtype_of(SystemDictionary::Cloneable_klass()); guarantee(cloneable == klass->is_cloneable(), "incorrect cloneable flag"); } #endif // Check if class of obj supports the Cloneable interface. // All arrays are considered to be cloneable (See JLS 20.1.5) if (!klass->is_cloneable()) { ResourceMark rm(THREAD); THROW_MSG_0(vmSymbols::java_lang_CloneNotSupportedException(), klass->external_name()); } // Make shallow object copy const int size = obj->size(); oop new_obj = NULL; if (obj->is_javaArray()) { const int length = ((arrayOop)obj())->length(); new_obj = CollectedHeap::array_allocate(klass, size, length, CHECK_NULL); } else { new_obj = CollectedHeap::obj_allocate(klass, size, CHECK_NULL); } // 4839641 (4840070): We must do an oop-atomic copy, because if another thread // is modifying a reference field in the clonee, a non-oop-atomic copy might // be suspended in the middle of copying the pointer and end up with parts // of two different pointers in the field. Subsequent dereferences will crash. // 4846409: an oop-copy of objects with long or double fields or arrays of same // won't copy the longs/doubles atomically in 32-bit vm's, so we copy jlongs instead // of oops. We know objects are aligned on a minimum of an jlong boundary. // The same is true of StubRoutines::object_copy and the various oop_copy // variants, and of the code generated by the inline_native_clone intrinsic. assert(MinObjAlignmentInBytes >= BytesPerLong, "objects misaligned"); Copy::conjoint_jlongs_atomic((jlong*)obj(), (jlong*)new_obj, (size_t)align_object_size(size) / HeapWordsPerLong); // Clear the header new_obj->init_mark(); // Store check (mark entire object and let gc sort it out) BarrierSet* bs = Universe::heap()->barrier_set(); assert(bs->has_write_region_opt(), "Barrier set does not have write_region"); bs->write_region(MemRegion((HeapWord*)new_obj, size)); // Caution: this involves a java upcall, so the clone should be // "gc-robust" by this stage. if (klass->has_finalizer()) { assert(obj->is_instance(), "should be instanceOop"); new_obj = instanceKlass::register_finalizer(instanceOop(new_obj), CHECK_NULL); } return JNIHandles::make_local(env, oop(new_obj)); JVM_END
我找到了这些文件，但他们所做的只是从其他地方导入函数。 我找不到实际的来源（尝试询问Hotspot dev）。
Object.c jvm.h
编辑： 这是在线实际源代码的链接 （感谢user439407查找它所在的文件）