I've found more strange code:
```java
if(this.readEventTypesLock.tryLock()) {
	this.readEventTypesLock.unlock();
}
else {
	this.writeEventTypesLock.lock();
	try {
		if(!this.supportsEventType(event.getClass())) {
			return;
		}
	}
	finally {
		this.writeEventTypesLock.unlock();
	}
}
```
but to me it seems less overhead to `this.supportsEventType`.
Sorry, I'm not still well with Java Concurrency :-)