Actually CMS is only five years older than G1. The first published papers for G1 are from 2004. But yes, G1 has a long history of scary bugs. There was a time a few years ago where practically every week a crashing bug was fixed.<p>G1 addresses certain problem areas of CMS and replaces them with others. Honestly I hope in ten years from now we have better choices in HotSpot than CMS or G1 but right now it doesn&#x27;t look like it (if you don&#x27;t count Shenandoah with has other issues).<p>Having that said I have recently seen G1 performing exceptionally well in production: 120ms GC pauses with a 120 MB&#x2F;s sustained allocation rate with basically default settings (apart from GC logging).