As I understand it, Java needs a complicated GC implementation because it produces, by design, a makes a huge amount of heap allocations -- lots of very short-l

As I understand it, Java needs a complicated GC implementation because it produces, by design, a makes a huge amount of heap allocations -- lots of very short-lived little objects. Much of Java's GC focus has been on correctly partitioning the heap so that long-lived objects can be less aggressively collected than short-lived ones. (An example of a challenging long-lived object is the entire set of classes used by a program, all of which need to available to the runtime for reflection. For many bigger apps, the class hierarchy alone takes up many megabytes of RAM!) Go can make use of the stack to a much larger degree (structs and arrays can be passed by value), and so it can get by with a much less advanced GC. As a result, Go team's main focus has been on reducing pause times more than anything else.