Why is null safety implemented in Dart and how does it help developers avoid errors?

Null safety in Dart is implemented through the null safety system. This means that variables by default cannot contain the value null unless explicitly specified.

How it helps:

• Prevents runtime errors: many errors in programs are related to attempting to access null (e.g., NullPointerException). With null safety, such errors are caught at compile time.
• Explicit indication of null possibility: if a variable can be null, it is explicitly indicated with ?, for example, String? name;. This forces the developer to handle such cases.
• Improves code readability and maintainability: the developer immediately sees which variables can be null and which cannot.

Example:

String name = 'Alice';
String? nickname;

print(name.length); // always safe

if (nickname != null) {
  print(nickname.length); // safe after check
}

Thus, null safety helps in writing more reliable and predictable code.