GC pauses are a popular topic, if you do a google search, you’ll see lots of articles explaining how to measure and more importantly how to reduce them. This issue is that in most runtimes that have a GC, allocating objects is a quick operation, but at some point in time the GC will need to clean up all the garbage and to do this is has to pause the entire runtime (except if you happen to be using Azul’s pauseless GC for Java).