Test-first development (TFD) is a software development methodology that emphasizes writing automated tests before writing any production code. The idea behind TFD is that by writing tests first, you can ensure that your code is correct, maintainable, and meets the requirements of the application.

In Java, TFD is typically done using a testing framework like JUnit or TestNG. Here are the basic steps involved in TFD:

1. Write a failing test: The first step in TFD is to write a test that specifies the behavior you want to implement. This test should fail initially, because you haven't written any code to implement the behavior yet.

2. Write the minimum amount of code to make the test pass: The next step is to write the minimum amount of code necessary to make the test pass. This code doesn't have to be perfect or complete yet; its only purpose is to make the test pass.

3. Refactor the code: Once the test passes, you can refactor the code to make it cleaner, more efficient, and more maintainable. This step is important, because it ensures that the code you write is of high quality and easy to work with.

4. Repeat: Repeat this process for each new feature or behavior you want to implement. By writing tests first and then implementing the behavior, you can be confident that your code works as expected and is easy to modify and maintain.

TFD can be a powerful methodology for building high-quality software, but it does require a certain level of discipline and skill. It's important to have a clear understanding of the requirements of the application, as well as a solid grasp of the testing framework you're using. It's also important to be willing to refactor your code and make changes as needed, in order to keep your code clean and maintainable. With practice and experience, TFD can become an effective way to build robust, high-quality software in Java.