Summary of features of SERIAL,PARALLEL,CMS,G1 four GC collectors

1.Serial Collector
A single-threaded collector that, during garbage collection, must suspend all other worker threads until it is collected.
Features: CPU utilization is highest, pause time is longer than user wait time.
Application Scenarios: Small applications
The serial garbage collector can be used with the JVM parameter-XX:+USESERIALGC.
2.Parallel Collector
use multiple threads to scan and compress the heap
Features: Short pause time, high recovery efficiency, high throughput requirements.
Application scenarios: Large-scale applications, scientific calculations, large-scale data collection, etc.
Open the Concurrency tag scan garbage collector with the JVM parameter XX:+USEPARNEWGC.
3.CMS Collector
using the "mark-and-sweep" algorithm, a multi-threaded algorithm is used to scan the heap to reclaim objects that are not used.
(1) Initial mark
(2) Concurrent tagging
(3) Concurrency preprocessing
(4) Re-tagging
(5) Concurrent cleanup
(6) Concurrent reset
Features: Response time priority, reduce garbage collection pause time
Adapt to the scene: servers, telecommunications and other fields.
Set by JVM parameter-XX:+USECONCMARKSWEEPGC
4.G1 Collector
in G1, the heap is divided into a number of contiguous regions (region). The G1 algorithm is used to recover and absorb the features of CMS collector.
Features: Large heap support, high throughput
--Support for multi-CPU and garbage collection threads
--using parallel collection in the case where the main thread is paused
--use concurrent collection in the case where the main thread is running
Real-time target: can be configured to consume up to m milliseconds for garbage collection in n milliseconds
Using the G1 garbage collector through the JVM parameter –XX:+USEG1GC