A new Flutter project to understand Null Safety in Flutter.

• Null Safety codelab
• sound Null safety
• Unsound Null safety

#What happens when Null safety is set as default?

1. All variables cannot be null. Non-nullable variables cannot be assigned as null. (TEST_NO_1)

   This causes Compile errors. It means you cannot even run the code.

2. Null check is not needed for non-nullable variable. (TEST_NO_2)

   This does not give compile error, but the program suggests to remove if statement.

3. variables "in Class" should be initialized as soon as it is declared.(TEST_NO_3)

   This also causes Compile error.

1. By adding '?' right after variable Type. It tells to Compiler that the variable cannot null.

null safety

• A Dart program can contain some libraries that are null safe and some that are not. These mixed-version programs execute with unsound null safety.

sound null safety

• When a program is fully migrated and all its libraries are null safe, then it runs with sound null safety, with all of the guarantees and compiler optimizations that soundness enables.