Unit testing is a vital aspect of software development, enabling developers to verify the correctness and reliability of individual units or components of code. Explore the principles and practices of unit testing in Java, including the concepts of static unit testing and dynamic unit testing. What are the key differences between static and dynamic unit testing approaches, and how do they complement each other in ensuring code quality and maintainability? Additionally, discuss the significance of writing effective test cases and utilizing testing frameworks such as JUnit in Java projects. How can unit testing contribute to the early detection and resolution of bugs, and how does it support the iterative and incremental development process? Finally, reflect on the challenges and best practices associated with incorporating unit testing into Java development workflows, considering factors such as test coverage, test$-$driven development $($TDD$),$ and continuous integration $($CI$)$ practices.