Enhanced garbage collector in Java 17

24 Oct 2023

Java 17, the latest release of the Java programming language, introduces several new features and improvements. One notable enhancement is an improved garbage collector (GC) algorithm. In this article, we’ll explore the changes made to the garbage collector in Java 17 and how it benefits developers.

Introduction to Garbage Collection

Garbage collection is a critical aspect of memory management in Java. It automatically frees up memory by removing objects that are no longer in use, allowing developers to focus on writing code rather than manual memory management.

Changes in Java 17 Garbage Collector

The garbage collector in Java 17 comes with several enhancements aimed at improving overall performance and reducing latency. Here are some of the key changes:

1. ZGC Pauses

Z Garbage Collector (ZGC), which was introduced in Java 11, focuses on minimizing GC pauses. In Java 17, ZGC further reduces the pauses by introducing concurrent stack processing. This allows the garbage collector to perform certain tasks concurrently with application threads, resulting in shorter pauses and better overall performance.

2. NUMA-Aware Allocation

Non-Uniform Memory Access (NUMA) is a memory architecture design that aims to improve performance by reducing memory latency. In Java 17, the garbage collector becomes NUMA-aware, which means it intelligently allocates objects to minimize memory access latency on NUMA systems. This improvement leads to better overall performance, especially on servers with NUMA architectures.

3. Efficient Heap Memory Management

Java 17 introduces improved heap memory management by reducing the footprint of some internal data structures. This enhancement results in more efficient memory utilization and can lead to performance improvements, especially in memory-constrained environments.

Benefits for Developers

The enhanced garbage collector in Java 17 brings several benefits for developers:

Reduced Latency: The concurrent stack processing in ZGC reduces GC pauses, resulting in reduced latency for applications. This is particularly beneficial for applications that require low response times and smooth user experiences.
Improved Performance: The NUMA-aware allocation and efficient heap memory management contribute to overall performance improvements. Applications running on NUMA systems or in resource-constrained environments may observe a noticeable performance boost.
Simplified Memory Management: With the enhancements in the garbage collector, developers can rely on the automatic memory management provided by Java without having to worry extensively about manual garbage collection and memory optimization.

Conclusion

Java 17’s enhanced garbage collector brings significant improvements to memory management, performance, and latency. Developers can benefit from reduced pauses, improved performance on NUMA systems, and simplified memory management. Upgrading to Java 17 allows developers to take advantage of these enhancements and improve the overall quality and efficiency of their Java applications.

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