This sample shows that applying 2 Hadamard gates brings the qubit back into the state it was in before applying the first Hadamard gate.
To run this application, simply run
mvn clean javafx:run
There is no relevant console output, but the following circuit will be shown:
This sample shows that the Hadamard gate is its own inverse. This is used in the next samples.
You can learn more about this sample in Chapter 8 of Quantum Computing for Java Developers. It is discussed in 8.4.1: "Applying 2 Hadamard gates"