arduino-serial | Example C and Java host code

Take a look at LinkedBlockingDeque or any other class that implements BlockingQueue. They have a take() method that blocks until the queue has an element available. As elements become available the take() method unblocks, and allows the processing code to execute.

I did something similar when I was waiting on serial data as I wanted to queue it for processing and process it sequentially.

In your listener class you would put elements into the queue:

As mentioned in the comments, don't use multi-character constants (the ones you used, with single quotes); they might kill puppies. Single quotes are for character constants, like 'a'.

You can use strings (with double quotes), or real binary numbers; without trickery, the latter will print without leading zeros.

This code example does both, so pick what you need: