Changed all field injection to constructor injection in NON-test classes

[JP-CC-Projects]

Why Constructor Injection?

One reason is that our unit tests may not work as expected.

As this helpful Baeldung article describes:

Other reasons:

• Ease of Testing: Makes writing unit tests easier and clearer because dependencies can be passed directly to the constructor in test setups, eliminating the need for reflection or Spring-specific annotations.
• No Spring Context Required: Allows for simpler unit tests that don't rely on Spring's context loading, leading to faster execution times.
• Immutability and Safety: Encourages immutability and clear dependency declaration, improving the overall safety and maintainability of your application.