The need for a way to execute concurrent tasks within Java has been addressed within JSE by the java.util.concurrent.Executor and in a limited fashion in JEE by the WorkManager specification.
State machines are so common that there are tools devoted to creating them by drawing circles and arts. There are simulators that will recognize your state machine ...
Most embedded systems are reactive by nature. They measure certain properties of their environment with sensors and react on changes. For example, they display something, move a motor, or send a ...