What are alternatives to G1 garbage collector and how do they compare?

Alternatives to G1 Garbage Collector

The G1 garbage collector (Garbage First) is one of the popular garbage collection algorithms in the Java Virtual Machine (JVM). However, there are several alternatives, each with its own advantages and use cases. Here we compare a few of them:

1. Serial Garbage Collector

The Serial GC is a simple garbage collector that uses a single thread for garbage collection, making it suitable for small applications with a single thread. It pauses all application threads during the collection process, leading to noticeable pauses in larger applications.

2. Parallel Garbage Collector

The Parallel GC, also known as the throughput collector, aims to maximize throughput by using multiple threads for garbage collection. It minimizes pause times but can still experience longer garbage collection pauses compared to G1.

3. Concurrent Mark-Sweep (CMS) Collector

The CMS collector is designed for applications that prefer shorter garbage collection pauses. It runs concurrently with the application, allowing it to minimize pause time significantly. However, it may lead to fragmentation and is not suitable for all scenarios.

4. Z Garbage Collector (ZGC)

ZGC is a low-latency garbage collector designed for applications that require predictable pause times, even with large heap sizes. It efficiently handles garbage collection in a way that minimizes stop-the-world pauses, making it suitable for modern applications.

5. Shenandoah Garbage Collector

Shenandoah is another low-pause-time garbage collector that aims to keep pause times short by performing most of its work concurrently with the application threads. It is designed for large heaps and aims to minimize latency.