diff --git a/include/cppcore/Common/TBitField.h b/include/cppcore/Common/TBitField.h
index 341f567..5162e45 100644
--- a/include/cppcore/Common/TBitField.h
+++ b/include/cppcore/Common/TBitField.h
@@ -41,7 +41,7 @@ class TBitField {
     
     /// @brief  The class constructor  with the initial value.
     /// @param[in] init The init value.
-    TBitField(T init);
+    explicit TBitField(T init);
     
     /// @brief  The class destructor.
     ~TBitField() = default;
diff --git a/include/cppcore/Common/TOptional.h b/include/cppcore/Common/TOptional.h
index 4d449a4..0007484 100644
--- a/include/cppcore/Common/TOptional.h
+++ b/include/cppcore/Common/TOptional.h
@@ -37,7 +37,7 @@ class TOptional {
 public:
     /// @brief  The class constructor.
     /// @param[in]  defaultValue    Init value if no set was performed.
-    TOptional(T defaultValue);
+    explicit TOptional(T defaultValue);
 
     /// @brief  The class destructor.
     ~TOptional() = default;
diff --git a/include/cppcore/Common/TStringBase.h b/include/cppcore/Common/TStringBase.h
index 33b5d17..2693c16 100644
--- a/include/cppcore/Common/TStringBase.h
+++ b/include/cppcore/Common/TStringBase.h
@@ -131,7 +131,7 @@ inline size_t TStringBase<T>::size() const {
 
 template <class T>
 inline bool TStringBase<T>::isEmpty() const {
-    return (mSize == 0);
+    return mSize == 0;
 }
 
 template <class T>
@@ -219,6 +219,9 @@ inline TStringBase<T>& TStringBase<T>::operator+=(char c) {
 
 template <class T>
 inline T TStringBase<T>::operator[](size_t index) const {
+    if (index >= mSize) {
+        return 0;
+    }
     return mBuffer[index];
 }