diff --git a/runtime/src/main/cpp/Exceptions.cpp b/runtime/src/main/cpp/Exceptions.cpp
index 3d901d6d8c2..2765d0f92e5 100644
--- a/runtime/src/main/cpp/Exceptions.cpp
+++ b/runtime/src/main/cpp/Exceptions.cpp
@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 #include "Assert.h"
 #include "Exceptions.h"
@@ -10,7 +12,7 @@ void ThrowNullPointerException() {
   void* pc = __builtin_return_address(0);
   char message[100];
   snprintf(message, sizeof(message), "NullPointerException at %p", pc);
-  fprintf(stderr, "%s\n", message);
+  write(STDOUT_FILENO, message, strlen(message));
   // TODO: throw it for real.
   RuntimeAssert(false, "Throwing is unsupported");
 }
@@ -19,11 +21,21 @@ void ThrowArrayIndexOutOfBoundsException() {
   void* pc = __builtin_return_address(0);
   char message[100];
   snprintf(message, sizeof(message), "ArrayIndexOutOfBoundsException at %p", pc);
-  fprintf(stderr, "%s\n", message);
+  write(STDOUT_FILENO, message, strlen(message));
   // TODO: throw it for real.
   RuntimeAssert(false, "Throwing is unsupported");
 }
 
+void ThrowClassCastException() {
+  void* pc = __builtin_return_address(0);
+  char message[100];
+  snprintf(message, sizeof(message), "ClassCastException at %p", pc);
+  write(STDOUT_FILENO, message, strlen(message));
+  // TODO: throw it for real.
+  RuntimeAssert(false, "Throwing is unsupported");
+}
+
+
 #ifdef __cplusplus
 } // extern "C"
 #endif
diff --git a/runtime/src/main/cpp/Exceptions.h b/runtime/src/main/cpp/Exceptions.h
index 2b4cff40828..185843331d7 100644
--- a/runtime/src/main/cpp/Exceptions.h
+++ b/runtime/src/main/cpp/Exceptions.h
@@ -1,7 +1,7 @@
 #ifndef RUNTIME_EXCEPTIONS_H
 #define RUNTIME_EXCEPTIONS_H
 
-#include <stdint.h>
+#include "Types.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -11,6 +11,8 @@ void ThrowNullPointerException();
 // Throws array index out of bounds exception.
 // Context is evaluated from caller's address.
 void ThrowArrayIndexOutOfBoundsException();
+// Throws class cast exception.
+void ThrowClassCastException();
 
 #ifdef __cplusplus
 } // extern "C"
diff --git a/runtime/src/main/cpp/Memory.h b/runtime/src/main/cpp/Memory.h
index 5ef2b88552c..fce850e9499 100644
--- a/runtime/src/main/cpp/Memory.h
+++ b/runtime/src/main/cpp/Memory.h
@@ -85,6 +85,12 @@ inline void* AddressOfElementAt(ArrayHeader* obj, int32_t index) {
       obj->type_info()->instanceSize_ * index;
 }
 
+inline const void* AddressOfElementAt(const ArrayHeader* obj, int32_t index) {
+  // Instance size is negative.
+  return reinterpret_cast<const uint8_t*>(obj + 1) -
+      obj->type_info()->instanceSize_ * index;
+}
+
 inline uint32_t ArrayDataSizeBytes(const ArrayHeader* obj) {
   // Instance size is negative.
   return -obj->type_info()->instanceSize_ * obj->count_;
diff --git a/runtime/src/main/cpp/Natives.h b/runtime/src/main/cpp/Natives.h
index 2c39b8d5ca1..5f678554b9a 100644
--- a/runtime/src/main/cpp/Natives.h
+++ b/runtime/src/main/cpp/Natives.h
@@ -1,23 +1,8 @@
 #ifndef RUNTIME_NATIVES_H
 #define RUNTIME_NATIVES_H
 
-#include "Memory.h"
 #include "Types.h"
 
-typedef uint8_t KBoolean;
-typedef int8_t KByte;
-typedef uint16_t KChar;
-// Note that it is signed.
-typedef int16_t KShort;
-typedef int32_t KInt;
-typedef int64_t KLong;
-typedef float   KFloat;
-typedef double  KDouble;
-
-typedef ObjHeader* KRef;
-typedef const ObjHeader* KConstRef;
-typedef const ArrayHeader* KString;
-
 // Optimized versions not accessing type info.
 inline KByte* ByteArrayAddressOfElementAt(ArrayHeader* obj, KInt index) {
   return reinterpret_cast<KByte*>(obj + 1) + index;
diff --git a/runtime/src/main/cpp/Types.h b/runtime/src/main/cpp/Types.h
index a712fad2bcb..f3e0cdea7a1 100644
--- a/runtime/src/main/cpp/Types.h
+++ b/runtime/src/main/cpp/Types.h
@@ -1,8 +1,23 @@
 #ifndef RUNTIME_TYPES_H
 #define RUNTIME_TYPES_H
 
+#include "Memory.h"
 #include "TypeInfo.h"
 
+// Note that almost all types are signed.
+typedef uint8_t KBoolean;
+typedef int8_t  KByte;
+typedef uint16_t KChar;
+typedef int16_t KShort;
+typedef int32_t KInt;
+typedef int64_t KLong;
+typedef float   KFloat;
+typedef double  KDouble;
+
+typedef ObjHeader* KRef;
+typedef const ObjHeader* KConstRef;
+typedef const ArrayHeader* KString;
+
 #ifdef __cplusplus
 extern "C" {
 #endif