--- a/hotspot/make/symbols/symbols-unix	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/make/symbols/symbols-unix	Thu Jan 19 11:49:30 2017 +0100
@@ -192,4 +192,3 @@
 JVM_AddReadsModule
 JVM_DefineModule
 JVM_SetBootLoaderUnnamedModule
-JVM_GetModuleByPackageName

--- a/hotspot/src/share/vm/classfile/modules.cpp	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/src/share/vm/classfile/modules.cpp	Thu Jan 19 11:49:30 2017 +0100
@@ -39,8 +39,6 @@
 #include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/instanceKlass.hpp"
-#include "oops/objArrayKlass.hpp"
-#include "oops/objArrayOop.inline.hpp"
 #include "runtime/arguments.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/javaCalls.hpp"
@@ -48,17 +46,17 @@
 #include "utilities/stringUtils.hpp"
 #include "utilities/utf8.hpp"
 
-static bool verify_module_name(char *module_name) {
+static bool verify_module_name(const char *module_name) {
   if (module_name == NULL) return false;
   int len = (int)strlen(module_name);
   return (len > 0 && len <= Symbol::max_length());
 }
 
-bool Modules::verify_package_name(char *package_name) {
+bool Modules::verify_package_name(const char* package_name) {
   if (package_name == NULL) return false;
   int len = (int)strlen(package_name);
   return (len > 0 && len <= Symbol::max_length() &&
-    UTF8::is_legal_utf8((unsigned char *)package_name, len, false) &&
+    UTF8::is_legal_utf8((const unsigned char *)package_name, len, false) &&
     ClassFileParser::verify_unqualified_name(package_name, len,
     ClassFileParser::LegalClass));
 }
@@ -107,10 +105,8 @@
   return java_lang_reflect_Module::module_entry(module_h(), CHECK_NULL);
 }
 
-static PackageEntry* get_package_entry(ModuleEntry* module_entry, jstring package, TRAPS) {
+static PackageEntry* get_package_entry(ModuleEntry* module_entry, const char* package_name, TRAPS) {
   ResourceMark rm(THREAD);
-  if (package == NULL) return NULL;
-  const char *package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
   if (package_name == NULL) return NULL;
   TempNewSymbol pkg_symbol = SymbolTable::new_symbol(package_name, CHECK_NULL);
   PackageEntryTable* package_entry_table = module_entry->loader_data()->packages();
@@ -139,7 +135,8 @@
 }
 
 static void define_javabase_module(jobject module, jstring version,
-                                   jstring location, jobjectArray packages, TRAPS) {
+                                   jstring location, const char* const* packages,
+                                   jsize num_packages, TRAPS) {
   ResourceMark rm(THREAD);
 
   Handle module_handle(THREAD, JNIHandles::resolve(module));
@@ -164,21 +161,12 @@
     }
   }
 
-  objArrayOop packages_oop = objArrayOop(JNIHandles::resolve(packages));
-  objArrayHandle packages_h(THREAD, packages_oop);
-  int num_packages = (packages_h == NULL ? 0 : packages_h->length());
 
   // Check that the list of packages has no duplicates and that the
   // packages are syntactically ok.
   GrowableArray<Symbol*>* pkg_list = new GrowableArray<Symbol*>(num_packages);
   for (int x = 0; x < num_packages; x++) {
-    oop string_obj = packages_h->obj_at(x);
-
-    if (string_obj == NULL || !string_obj->is_a(SystemDictionary::String_klass())) {
-      THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
-                "Bad package name for module: " JAVA_BASE_NAME);
-    }
-    char *package_name = java_lang_String::as_utf8_string(string_obj);
+    const char *package_name = packages[x];
     if (!Modules::verify_package_name(package_name)) {
       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
                 err_msg("Invalid package name: %s for module: " JAVA_BASE_NAME, package_name));
@@ -277,12 +265,24 @@
 }
 
 void Modules::define_module(jobject module, jstring version,
-                            jstring location, jobjectArray packages, TRAPS) {
+                            jstring location, const char* const* packages,
+                            jsize num_packages, TRAPS) {
   ResourceMark rm(THREAD);
 
   if (module == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(), "Null module object");
   }
+
+  if (num_packages < 0) {
+    THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+              "num_packages must be >= 0");
+  }
+
+  if (packages == NULL && num_packages > 0) {
+    THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+              "num_packages should be zero if packages is null");
+  }
+
   Handle module_handle(THREAD, JNIHandles::resolve(module));
   if (!java_lang_reflect_Module::is_instance(module_handle())) {
     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
@@ -297,7 +297,7 @@
 
   // Special handling of java.base definition
   if (strcmp(module_name, JAVA_BASE_NAME) == 0) {
-    define_javabase_module(module, version, location, packages, CHECK);
+    define_javabase_module(module, version, location, packages, num_packages, CHECK);
     return;
   }
 
@@ -311,21 +311,11 @@
   }
   Handle h_loader = Handle(THREAD, loader);
 
-  objArrayOop packages_oop = objArrayOop(JNIHandles::resolve(packages));
-  objArrayHandle packages_h(THREAD, packages_oop);
-  int num_packages = (packages_h == NULL ? 0 : packages_h->length());
-
   // Check that the list of packages has no duplicates and that the
   // packages are syntactically ok.
   GrowableArray<Symbol*>* pkg_list = new GrowableArray<Symbol*>(num_packages);
   for (int x = 0; x < num_packages; x++) {
-    oop string_obj = packages_h->obj_at(x);
-
-    if (string_obj == NULL || !string_obj->is_a(SystemDictionary::String_klass())) {
-      THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
-                err_msg("Bad package name for module: %s", module_name));
-    }
-    char *package_name = java_lang_String::as_utf8_string(string_obj);
+    const char* package_name = packages[x];
     if (!verify_package_name(package_name)) {
       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
                 err_msg("Invalid package name: %s for module: %s",
@@ -337,12 +327,15 @@
         !SystemDictionary::is_platform_class_loader(h_loader) &&
         strncmp(package_name, JAVAPKG, JAVAPKG_LEN) == 0) {
       const char* class_loader_name = SystemDictionary::loader_name(h_loader());
-      StringUtils::replace_no_expand(package_name, "/", ".");
+      size_t pkg_len = strlen(package_name);
+      char* pkg_name = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, pkg_len);
+      strncpy(pkg_name, package_name, pkg_len);
+      StringUtils::replace_no_expand(pkg_name, "/", ".");
       const char* msg_text1 = "Class loader (instance of): ";
       const char* msg_text2 = " tried to define prohibited package name: ";
-      size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(package_name) + 1;
+      size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + pkg_len + 1;
       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
-      jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, package_name);
+      jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, pkg_name);
       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), message);
     }
 
@@ -506,8 +499,8 @@
   java_lang_reflect_Module::set_module_entry(module_handle(), unnamed_module);
 }
 
-void Modules::add_module_exports(jobject from_module, jstring package, jobject to_module, TRAPS) {
-  if (package == NULL) {
+void Modules::add_module_exports(jobject from_module, const char* package_name, jobject to_module, TRAPS) {
+  if (package_name == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
               "package is null");
   }
@@ -535,10 +528,9 @@
     }
   }
 
-  PackageEntry *package_entry = get_package_entry(from_module_entry, package, CHECK);
+  PackageEntry *package_entry = get_package_entry(from_module_entry, package_name, CHECK);
   ResourceMark rm(THREAD);
   if (package_entry == NULL) {
-    const char *package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
               err_msg("Package %s not found in from_module %s",
                       package_name != NULL ? package_name : "",
@@ -566,7 +558,7 @@
 }
 
 
-void Modules::add_module_exports_qualified(jobject from_module, jstring package,
+void Modules::add_module_exports_qualified(jobject from_module, const char* package,
                                            jobject to_module, TRAPS) {
   if (to_module == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
@@ -658,21 +650,15 @@
 }
 
 
-jobject Modules::get_module_by_package_name(jobject loader, jstring package, TRAPS) {
+jobject Modules::get_module_by_package_name(jobject loader, const char* package_name, TRAPS) {
   ResourceMark rm(THREAD);
   assert(ModuleEntryTable::javabase_defined(),
          "Attempt to call get_module_from_pkg before " JAVA_BASE_NAME " is defined");
 
-  if (NULL == package) {
+  if (package_name == NULL) {
     THROW_MSG_(vmSymbols::java_lang_NullPointerException(),
                "package is null", JNI_FALSE);
   }
-  const char* package_str =
-    java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
-  if (NULL == package_str) {
-    THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),
-               "Invalid package", JNI_FALSE);
-  }
 
   Handle h_loader (THREAD, JNIHandles::resolve(loader));
   // Check that loader is a subclass of java.lang.ClassLoader.
@@ -681,7 +667,7 @@
                "Class loader is not a subclass of java.lang.ClassLoader", JNI_FALSE);
   }
 
-  if (strlen(package_str) == 0) {
+  if (strlen(package_name) == 0) {
     // Return the unnamed module
     ModuleEntryTable* module_table = get_module_entry_table(h_loader, CHECK_NULL);
     if (NULL == module_table) return NULL;
@@ -689,24 +675,24 @@
     return JNIHandles::make_local(THREAD, JNIHandles::resolve(unnamed_module->module()));
 
   } else {
-    TempNewSymbol package_sym = SymbolTable::new_symbol(package_str, CHECK_NULL);
+    TempNewSymbol package_sym = SymbolTable::new_symbol(package_name, CHECK_NULL);
     return get_module(package_sym, h_loader, CHECK_NULL);
   }
   return NULL;
 }
 
 
-jobject Modules::get_named_module(Handle h_loader, const char* package_str, TRAPS) {
+jobject Modules::get_named_module(Handle h_loader, const char* package_name, TRAPS) {
   assert(ModuleEntryTable::javabase_defined(),
          "Attempt to call get_named_module before " JAVA_BASE_NAME " is defined");
   assert(h_loader.is_null() || java_lang_ClassLoader::is_subclass(h_loader->klass()),
          "Class loader is not a subclass of java.lang.ClassLoader");
-  assert(package_str != NULL, "the package_str should not be NULL");
+  assert(package_name != NULL, "the package_name should not be NULL");
 
-  if (strlen(package_str) == 0) {
+  if (strlen(package_name) == 0) {
     return NULL;
   }
-  TempNewSymbol package_sym = SymbolTable::new_symbol(package_str, CHECK_NULL);
+  TempNewSymbol package_sym = SymbolTable::new_symbol(package_name, CHECK_NULL);
   const PackageEntry* const pkg_entry =
     get_package_entry_by_name(package_sym, h_loader, THREAD);
   const ModuleEntry* const module_entry = (pkg_entry != NULL ? pkg_entry->module() : NULL);
@@ -732,14 +718,14 @@
   return NULL;
 }
 
-void Modules::add_module_package(jobject module, jstring package, TRAPS) {
+void Modules::add_module_package(jobject module, const char* package_name, TRAPS) {
   ResourceMark rm(THREAD);
 
   if (module == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
               "module is null");
   }
-  if (package == NULL) {
+  if (package_name == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
               "package is null");
   }
@@ -752,11 +738,6 @@
     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
               "module cannot be an unnamed module");
   }
-  char *package_name = java_lang_String::as_utf8_string(
-    JNIHandles::resolve_non_null(package));
-  if (package_name == NULL) {
-    THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "Bad package");
-  }
   if (!verify_package_name(package_name)) {
     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
               err_msg("Invalid package name: %s", package_name));
@@ -769,12 +750,15 @@
       !loader_data->is_platform_class_loader_data() &&
       strncmp(package_name, JAVAPKG, JAVAPKG_LEN) == 0) {
     const char* class_loader_name = SystemDictionary::loader_name(loader_data);
-    StringUtils::replace_no_expand(package_name, "/", ".");
+    size_t pkg_len = strlen(package_name);
+    char* pkg_name = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, pkg_len);
+    strncpy(pkg_name, package_name, pkg_len);
+    StringUtils::replace_no_expand(pkg_name, "/", ".");
     const char* msg_text1 = "Class loader (instance of): ";
     const char* msg_text2 = " tried to define prohibited package name: ";
-    size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(package_name) + 1;
+    size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + pkg_len + 1;
     char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
-    jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, package_name);
+    jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, pkg_name);
     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), message);
   }
 
@@ -802,12 +786,12 @@
 }
 
 // Export package in module to all unnamed modules.
-void Modules::add_module_exports_to_all_unnamed(jobject module, jstring package, TRAPS) {
+void Modules::add_module_exports_to_all_unnamed(jobject module, const char* package_name, TRAPS) {
   if (module == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
               "module is null");
   }
-  if (package == NULL) {
+  if (package_name == NULL) {
     THROW_MSG(vmSymbols::java_lang_NullPointerException(),
               "package is null");
   }
@@ -818,10 +802,9 @@
   }
 
   if (module_entry->is_named()) { // No-op for unnamed module.
-    PackageEntry *package_entry = get_package_entry(module_entry, package, CHECK);
+    PackageEntry *package_entry = get_package_entry(module_entry, package_name, CHECK);
     ResourceMark rm(THREAD);
     if (package_entry == NULL) {
-      const char *package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
                 err_msg("Package %s not found in module %s",
                         package_name != NULL ? package_name : "",

--- a/hotspot/src/share/vm/classfile/modules.hpp	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/src/share/vm/classfile/modules.hpp	Thu Jan 19 11:49:30 2017 +0100
@@ -48,9 +48,12 @@
   // * Packages contains a duplicate package name
   // * A package already exists in another module for this class loader
   // * Module is an unnamed module
+  // * num_packages is negative
+  // * num_packages is non-zero when packages is null
   //  NullPointerExceptions are thrown if module is null.
   static void define_module(jobject module, jstring version,
-                            jstring location, jobjectArray packages, TRAPS);
+                            jstring location, const char* const* packages,
+                            jsize num_packages, TRAPS);
 
   // Provides the java.lang.reflect.Module for the unnamed module defined
   // to the boot loader.
@@ -72,7 +75,7 @@
   // * Package is not syntactically correct
   // * Package is not defined for from_module's class loader
   // * Package is not in module from_module.
-  static void add_module_exports(jobject from_module, jstring package, jobject to_module, TRAPS);
+  static void add_module_exports(jobject from_module, const char* package, jobject to_module, TRAPS);
 
   // This does a qualified export of package in module from_module to module
   // to_module.  The format for the package name must use "/' not ".".
@@ -83,7 +86,7 @@
   // * Package is not syntactically correct
   // * Package is not defined for from_module's class loader
   // * Package is not in module from_module.
-  static void add_module_exports_qualified(jobject from_module, jstring package, jobject to_module, TRAPS);
+  static void add_module_exports_qualified(jobject from_module, const char* package, jobject to_module, TRAPS);
 
   // add_reads_module adds module to_module to the list of modules that from_module
   // can read.  If from_module is the same as to_module then this is a no-op.
@@ -102,7 +105,7 @@
   // NullPointerException is thrown if package is null.
   // IllegalArgumentException is thrown if loader is neither null nor a subtype of
   // java/lang/ClassLoader.
-  static jobject get_module_by_package_name(jobject loader, jstring package, TRAPS);
+  static jobject get_module_by_package_name(jobject loader, const char* package, TRAPS);
   static jobject get_named_module(Handle h_loader, const char* package, TRAPS);
 
   // If package is defined by loader, return the
@@ -116,16 +119,16 @@
   // * Module is unnamed
   // * Package is not syntactically correct
   // * Package is already defined for module's class loader.
-  static void add_module_package(jobject module, jstring package, TRAPS);
+  static void add_module_package(jobject module, const char* package, TRAPS);
 
   // Marks the specified package as exported to all unnamed modules.
   // If either module or package is null then NullPointerException is thrown.
   // If module or package is bad, or module is unnamed, or package is not in
   // module then IllegalArgumentException is thrown.
-  static void add_module_exports_to_all_unnamed(jobject module, jstring package, TRAPS);
+  static void add_module_exports_to_all_unnamed(jobject module, const char* package, TRAPS);
 
   // Return TRUE if package_name is syntactically valid, false otherwise.
-  static bool verify_package_name(char *package_name);
+  static bool verify_package_name(const char *package_name);
 
   // Return TRUE iff package is defined by loader
   static bool is_package_defined(Symbol* package_name, Handle h_loader, TRAPS);

--- a/hotspot/src/share/vm/prims/jvm.cpp	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/src/share/vm/prims/jvm.cpp	Thu Jan 19 11:49:30 2017 +0100
@@ -1009,9 +1009,9 @@
 // Module support //////////////////////////////////////////////////////////////////////////////
 
 JVM_ENTRY(void, JVM_DefineModule(JNIEnv *env, jobject module, jboolean is_open, jstring version,
-                                 jstring location, jobjectArray packages))
+                                 jstring location, const char* const* packages, jsize num_packages))
   JVMWrapper("JVM_DefineModule");
-  Modules::define_module(module, version, location, packages, CHECK);
+  Modules::define_module(module, version, location, packages, num_packages, CHECK);
 JVM_END
 
 JVM_ENTRY(void, JVM_SetBootLoaderUnnamedModule(JNIEnv *env, jobject module))
@@ -1019,17 +1019,17 @@
   Modules::set_bootloader_unnamed_module(module, CHECK);
 JVM_END
 
-JVM_ENTRY(void, JVM_AddModuleExports(JNIEnv *env, jobject from_module, jstring package, jobject to_module))
+JVM_ENTRY(void, JVM_AddModuleExports(JNIEnv *env, jobject from_module, const char* package, jobject to_module))
   JVMWrapper("JVM_AddModuleExports");
   Modules::add_module_exports_qualified(from_module, package, to_module, CHECK);
 JVM_END
 
-JVM_ENTRY(void, JVM_AddModuleExportsToAllUnnamed(JNIEnv *env, jobject from_module, jstring package))
+JVM_ENTRY(void, JVM_AddModuleExportsToAllUnnamed(JNIEnv *env, jobject from_module, const char* package))
   JVMWrapper("JVM_AddModuleExportsToAllUnnamed");
   Modules::add_module_exports_to_all_unnamed(from_module, package, CHECK);
 JVM_END
 
-JVM_ENTRY(void, JVM_AddModuleExportsToAll(JNIEnv *env, jobject from_module, jstring package))
+JVM_ENTRY(void, JVM_AddModuleExportsToAll(JNIEnv *env, jobject from_module, const char* package))
   JVMWrapper("JVM_AddModuleExportsToAll");
   Modules::add_module_exports(from_module, package, NULL, CHECK);
 JVM_END
@@ -1039,16 +1039,11 @@
   Modules::add_reads_module(from_module, source_module, CHECK);
 JVM_END
 
-JVM_ENTRY (void, JVM_AddModulePackage(JNIEnv *env, jobject module, jstring package))
+JVM_ENTRY (void, JVM_AddModulePackage(JNIEnv *env, jobject module, const char* package))
   JVMWrapper("JVM_AddModulePackage");
   Modules::add_module_package(module, package, CHECK);
 JVM_END
 
-JVM_ENTRY (jobject, JVM_GetModuleByPackageName(JNIEnv *env, jobject loader, jstring package))
-  JVMWrapper("JVM_GetModuleByPackageName");
-  return Modules::get_module_by_package_name(loader, package, THREAD);
-JVM_END
-
 // Reflection support //////////////////////////////////////////////////////////////////////////////
 
 JVM_ENTRY(jstring, JVM_GetClassName(JNIEnv *env, jclass cls))

--- a/hotspot/src/share/vm/prims/jvm.h	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/src/share/vm/prims/jvm.h	Thu Jan 19 11:49:30 2017 +0100
@@ -412,30 +412,67 @@
  * Module support funcions
  */
 
+/*
+ * Define a module with the specified packages and bind the module to the
+ * given class loader.
+ *  module:       module to define
+ *  is_open:      specifies if module is open (currently ignored)
+ *  version:      the module version
+ *  location:     the module location
+ *  packages:     list of packages in the module
+ *  num_packages: number of packages in the module
+ */
 JNIEXPORT void JNICALL
 JVM_DefineModule(JNIEnv *env, jobject module, jboolean is_open, jstring version,
-                 jstring location, jobjectArray packages);
+                 jstring location, const char* const* packages, jsize num_packages);
 
+/*
+ * Set the boot loader's unnamed module.
+ *  module: boot loader's unnamed module
+ */
 JNIEXPORT void JNICALL
 JVM_SetBootLoaderUnnamedModule(JNIEnv *env, jobject module);
 
+/*
+ * Do a qualified export of a package.
+ *  from_module: module containing the package to export
+ *  package:     name of the package to export
+ *  to_module:   module to export the package to
+ */
 JNIEXPORT void JNICALL
-JVM_AddModuleExports(JNIEnv *env, jobject from_module, jstring package, jobject to_module);
+JVM_AddModuleExports(JNIEnv *env, jobject from_module, const char* package, jobject to_module);
 
+/*
+ * Do an export of a package to all unnamed modules.
+ *  from_module: module containing the package to export
+ *  package:     name of the package to export to all unnamed modules
+ */
 JNIEXPORT void JNICALL
-JVM_AddModuleExportsToAllUnnamed(JNIEnv *env, jobject from_module, jstring package);
+JVM_AddModuleExportsToAllUnnamed(JNIEnv *env, jobject from_module, const char* package);
 
+/*
+ * Do an unqualified export of a package.
+ *  from_module: module containing the package to export
+ *  package:     name of the package to export
+ */
 JNIEXPORT void JNICALL
-JVM_AddModuleExportsToAll(JNIEnv *env, jobject from_module, jstring package);
+JVM_AddModuleExportsToAll(JNIEnv *env, jobject from_module, const char* package);
 
+/*
+ * Add a module to the list of modules that a given module can read.
+ *  from_module:   module requesting read access
+ *  source_module: module that from_module wants to read
+ */
 JNIEXPORT void JNICALL
 JVM_AddReadsModule(JNIEnv *env, jobject from_module, jobject source_module);
 
+/*
+ * Add a package to a module.
+ *  module:  module that will contain the package
+ *  package: package to add to the module
+ */
 JNIEXPORT void JNICALL
-JVM_AddModulePackage(JNIEnv* env,  jobject module, jstring package);
-
-JNIEXPORT jobject JNICALL
-JVM_GetModuleByPackageName(JNIEnv* env, jobject loader, jstring package);
+JVM_AddModulePackage(JNIEnv* env,  jobject module, const char* package);
 
 /*
  * Reflection support functions

--- a/hotspot/src/share/vm/prims/whitebox.cpp	Thu Jan 19 11:10:33 2017 +0100
+++ b/hotspot/src/share/vm/prims/whitebox.cpp	Thu Jan 19 11:49:30 2017 +0100
@@ -40,6 +40,8 @@
 #include "memory/universe.hpp"
 #include "memory/oopFactory.hpp"
 #include "oops/constantPool.hpp"
+#include "oops/objArrayKlass.hpp"
+#include "oops/objArrayOop.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/wbtestmethods/parserTests.hpp"
 #include "prims/whitebox.hpp"
@@ -1403,19 +1405,52 @@
 
 WB_ENTRY(void, WB_DefineModule(JNIEnv* env, jobject o, jobject module, jstring version, jstring location,
                                 jobjectArray packages))
-  Modules::define_module(module, version, location, packages, CHECK);
+  ResourceMark rm(THREAD);
+
+  objArrayOop packages_oop = objArrayOop(JNIHandles::resolve(packages));
+  objArrayHandle packages_h(THREAD, packages_oop);
+  int num_packages = (packages_h == NULL ? 0 : packages_h->length());
+
+  char** pkgs = NULL;
+  if (num_packages > 0) {
+    pkgs = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char*, num_packages);
+    for (int x = 0; x < num_packages; x++) {
+      oop pkg_str = packages_h->obj_at(x);
+      if (pkg_str == NULL || !pkg_str->is_a(SystemDictionary::String_klass())) {
+        THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),
+                  err_msg("Bad package name"));
+      }
+      pkgs[x] = java_lang_String::as_utf8_string(pkg_str);
+    }
+  }
+  Modules::define_module(module, version, location, (const char* const*)pkgs, num_packages, CHECK);
 WB_END
 
 WB_ENTRY(void, WB_AddModuleExports(JNIEnv* env, jobject o, jobject from_module, jstring package, jobject to_module))
-  Modules::add_module_exports_qualified(from_module, package, to_module, CHECK);
+  ResourceMark rm(THREAD);
+  char* package_name = NULL;
+  if (package != NULL) {
+      package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
+  }
+  Modules::add_module_exports_qualified(from_module, package_name, to_module, CHECK);
 WB_END
 
 WB_ENTRY(void, WB_AddModuleExportsToAllUnnamed(JNIEnv* env, jobject o, jclass module, jstring package))
-  Modules::add_module_exports_to_all_unnamed(module, package, CHECK);
+  ResourceMark rm(THREAD);
+  char* package_name = NULL;
+  if (package != NULL) {
+      package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
+  }
+  Modules::add_module_exports_to_all_unnamed(module, package_name, CHECK);
 WB_END
 
 WB_ENTRY(void, WB_AddModuleExportsToAll(JNIEnv* env, jobject o, jclass module, jstring package))
-  Modules::add_module_exports(module, package, NULL, CHECK);
+  ResourceMark rm(THREAD);
+  char* package_name = NULL;
+  if (package != NULL) {
+      package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
+  }
+  Modules::add_module_exports(module, package_name, NULL, CHECK);
 WB_END
 
 WB_ENTRY(void, WB_AddReadsModule(JNIEnv* env, jobject o, jobject from_module, jobject source_module))
@@ -1423,11 +1458,21 @@
 WB_END
 
 WB_ENTRY(void, WB_AddModulePackage(JNIEnv* env, jobject o, jclass module, jstring package))
-  Modules::add_module_package(module, package, CHECK);
+  ResourceMark rm(THREAD);
+  char* package_name = NULL;
+  if (package != NULL) {
+      package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
+  }
+  Modules::add_module_package(module, package_name, CHECK);
 WB_END
 
 WB_ENTRY(jobject, WB_GetModuleByPackageName(JNIEnv* env, jobject o, jobject loader, jstring package))
-  return Modules::get_module_by_package_name(loader, package, THREAD);
+  ResourceMark rm(THREAD);
+  char* package_name = NULL;
+  if (package != NULL) {
+      package_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(package));
+  }
+  return Modules::get_module_by_package_name(loader, package_name, THREAD);
 WB_END
 
 WB_ENTRY(jlong, WB_IncMetaspaceCapacityUntilGC(JNIEnv* env, jobject wb, jlong inc))