源码位置：art/runtime/jni/jni_env_ext.cc
头文件位置：art/runtime/jni/jni_env_ext.h

JNIEnvExt类

 40 class JNIEnvExt : public JNIEnv {

实例化方法

• Create

  67 JNIEnvExt* JNIEnvExt::Create(Thread* self_in, JavaVMExt* vm_in, std::string* error_msg) {
  68   std::unique_ptr<JNIEnvExt> ret(new JNIEnvExt(self_in, vm_in, error_msg));
  69   if (CheckLocalsValid(ret.get())) {
  70     return ret.release();
  71   }
  72   return nullptr;
  73 }

  方法调用位置：
  Thread::Init和Thread::CreateNativeThread

• 构造方法

  75 JNIEnvExt::JNIEnvExt(Thread* self_in, JavaVMExt* vm_in, std::string* error_msg)
  76     : self_(self_in),
  77       vm_(vm_in),
  78       local_ref_cookie_(kIRTFirstSegment),
  79       locals_(kLocalsInitial, kLocal, IndirectReferenceTable::ResizableCapacity::kYes, error_msg),
  80       monitors_("monitors", kMonitorsInitial, kMonitorsMax),
  81       critical_(0),
  82       check_jni_(false),
  83       runtime_deleted_(false) {
  84   MutexLock mu(Thread::Current(), *Locks::jni_function_table_lock_);
  85   check_jni_ = vm_in->IsCheckJniEnabled();
  86   functions = GetFunctionTable(check_jni_);
  87   unchecked_functions_ = GetJniNativeInterface();
  88 }