Latch that can be incremented

You could also use a Phaser (java.util.concurrent.Phaser)

final Phaser phaser = new Phaser(1); // register self
while (/* some condition */) {
    phaser.register(); // Equivalent to countUp
    // do some work asynchronously, invoking
    // phaser.arriveAndDeregister() (equiv to countDown) in a finally block
}
phaser.arriveAndAwaitAdvance(); // await any async tasks to complete