Java was rarely used for that kind of things, but now it is used widely. There's a new crop of Java databases, starting from Apache Cassandra and towards memor

Java was rarely used for that kind of things, but now it is used widely. There's a new crop of Java databases, starting from Apache Cassandra and towards memory grids such as Apache Ignite or Apache Geode. And they benefit tremendously from access to Unsafe. Yes it's probably 1% of code ever written in Java by line count, but with potential of being 20-50% by CPU and RAM usage. It is sine qua non, a vital piece of infrastructure.