diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5761fdf..5b0df27 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,7 +1,11 @@
 set(SRC_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/jaclks-internal)
 
-aux_source_directory(${SRC_ROOT_DIR}/javac-base/java/lang SRC_FILES)
-aux_source_directory(${SRC_ROOT_DIR}/javac-base/java/security SRC_FILES)
+set(CXX_SRC_ROOT_DIR ${SRC_ROOT_DIR}/cxx-detail)
+aux_source_directory(${CXX_SRC_ROOT_DIR}/utils SRC_FILES)
+
+set(JBASE_SRC_ROOT_DIR ${SRC_ROOT_DIR}/javac-base)
+aux_source_directory(${JBASE_SRC_ROOT_DIR}/java/lang SRC_FILES)
+aux_source_directory(${JBASE_SRC_ROOT_DIR}/java/security SRC_FILES)
 
 if(BUILD_SHARED_LIBS)
   add_library(jaclks_shared SHARED ${SRC_FILES})
diff --git a/src/jaclks-internal/cxx-detail/utils/string_utils.cc b/src/jaclks-internal/cxx-detail/utils/string_utils.cc
new file mode 100644
index 0000000..be783ce
--- /dev/null
+++ b/src/jaclks-internal/cxx-detail/utils/string_utils.cc
@@ -0,0 +1,62 @@
+#include "jaclks-internal/cxx-detail/utils/string_utils.h"
+
+namespace jaclks::cxx_detail {
+
+namespace {
+using std::string;
+
+/**
+ * Steal to access private _M_string_length member
+ */
+using size_type = string::size_type;
+
+size_type *StealLength(string *str);
+
+template <size_type string::*MEMBER_INT_PTR>
+struct LengthMemberAccesser {
+  friend size_type *StealLength(string *victim_object) {
+    return &(victim_object->*MEMBER_INT_PTR);
+  }
+};
+
+template struct LengthMemberAccesser<&string::_M_string_length>;
+
+/**
+ * Steal local capacity
+ */
+int StealLocalCapacity(const string &str);
+
+template <int Cap>
+struct LocalCapacityMemberAccesser {
+  friend int StealLocalCapacity(const string &victim_object) {
+    return Cap;
+  }
+};
+
+template struct LocalCapacityMemberAccesser<string::_S_local_capacity>;
+
+/**
+ * Steal to access private _M_is_local function
+ */
+bool IsLocalData(const string &str);
+
+template <bool (string::*Func)() const>
+struct LocalFunctionAccesser {
+  friend bool IsLocalData(const string &victim_object) {
+    return (victim_object.*Func)();
+    ;
+  }
+};
+
+template struct LocalFunctionAccesser<&string::_M_is_local>;
+
+}  // namespace
+
+std::string StringUtils::ToStdString(javac_base::String str) {
+  std::string result;
+
+
+  return "";
+}
+
+}  // namespace jaclks::cxx_detail
diff --git a/src/jaclks-internal/cxx-detail/utils/string_utils.h b/src/jaclks-internal/cxx-detail/utils/string_utils.h
new file mode 100644
index 0000000..7d928d6
--- /dev/null
+++ b/src/jaclks-internal/cxx-detail/utils/string_utils.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <string>
+
+#include "jaclks/javac-base/java/lang/string.h"
+
+namespace jaclks::cxx_detail {
+
+class StringUtils {
+ public:
+  static std::string ToStdString(javac_base::String str);
+};
+
+}  // namespace jaclks::cxx_detail
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index ad4a764..8a0efaa 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -8,6 +8,7 @@ add_executable(jaclks_gtest main.cc ${SRC_FILES} ${TEST_SRC_FILES})
 
 target_link_libraries(jaclks_gtest PRIVATE GTest::gtest)
 
+add_subdirectory(cxx-detail)
 add_subdirectory(javac-base)
 
 # Registers googletests
diff --git a/tests/cxx-detail/CMakeLists.txt b/tests/cxx-detail/CMakeLists.txt
new file mode 100644
index 0000000..5225770
--- /dev/null
+++ b/tests/cxx-detail/CMakeLists.txt
@@ -0,0 +1,14 @@
+include_directories(${PROJECT_ROOT_DIR}/src)
+
+# add all test files
+aux_source_directory(${CMAKE_CURRENT_SOURCE_DIR}/utils JCXX_TEST_SRC_FILES)
+
+add_executable(jcxx_gtest main.cc ${JCXX_TEST_SRC_FILES})
+
+target_link_libraries(jcxx_gtest PRIVATE MyThirdParty::All jaclks_static
+                                         GTest::gtest)
+
+add_dependencies(jcxx_gtest jaclks_static)
+
+# Registers googletests
+add_test(NAME jcxx_gtest COMMAND $<TARGET_FILE:jcxx_gtest>)
diff --git a/tests/cxx-detail/main.cc b/tests/cxx-detail/main.cc
new file mode 100644
index 0000000..4d820af
--- /dev/null
+++ b/tests/cxx-detail/main.cc
@@ -0,0 +1,6 @@
+#include <gtest/gtest.h>
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/tests/cxx-detail/utils/string_utils_test.cc b/tests/cxx-detail/utils/string_utils_test.cc
new file mode 100644
index 0000000..fe3904a
--- /dev/null
+++ b/tests/cxx-detail/utils/string_utils_test.cc
@@ -0,0 +1,9 @@
+#include "jaclks-internal/cxx-detail/utils/string_utils.h"
+
+#include <gtest/gtest.h>
+
+namespace jaclks::cxx_detail {
+
+TEST(StringUtils, ToStdString) {}
+
+}  // namespace jaclks::cxx_detail