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This article walks through a real‑world production case, detailing how to systematically detect, analyze, and resolve severe JVM garbage‑collection pauses in a high‑concurrency Spring Boot microservice, covering resource analysis, JVM flag tuning, G1GC migration, JMX listeners, and GC‑log investigation.
After upgrading to JDK 11 and switching to G1GC, the author observed memory usage exceeding 90% due to G1 Old GC not reclaiming space, and provides a detailed analysis of the issue, including heap inspection, GC mechanisms, and practical tuning solutions such as adjusting heap size and G1GC parameters.
The investigation revealed that G1GC pauses were caused by uncontrolled growth of the JVM StringTable, triggered by Jackson’s InternCache interning countless random JSON field names, and was mitigated by enlarging the young generation, disabling field‑name interning, tuning G1 parameters, and monitoring StringTable size.
This article details a step‑by‑step investigation of a container whose memory usage spiked to 99% due to large objects being allocated to the old generation under G1GC, explains the root cause, demonstrates reproducible tests with JVM flags and monitoring tools, and provides practical mitigation strategies.
This article explains the G1 garbage collector’s heap layout, collection cycles, pause prediction, log analysis, and monitoring tools, helping Java developers diagnose and resolve performance issues such as frequent restarts, OOM, CPU spikes, and periodic latency spikes.
The article investigates intermittent long G1GC pauses in a Java 1.8 application caused by mis‑configured G1 parameters and MySQL driver phantom references that retain many idle connections, then presents detailed log analysis and multiple remediation steps including JVM flag tuning, connection‑pool adjustments, and driver upgrades.
This article details a comprehensive investigation of an out‑of‑memory crash in a critical Elasticsearch cluster, explains how GC logs and heap dumps revealed a to‑space‑exhausted condition, and describes the G1GC tuning parameters that eliminated the nightly spikes and stabilized performance.
The article provides a hands‑on migration guide for moving an internal gateway service from Java 8 to JDK 11 with the G1 garbage collector, detailing a checklist of tool and dependency updates, showcasing up to 105 % performance gains, outlining new language features, virtual‑thread usage, and best‑practice recommendations for a smooth, cost‑effective upgrade.
The investigation revealed that repeatedly creating XStream objects generated thousands of CompositeClassLoader instances, inflating the JVM’s SystemDictionary and causing extremely long Ext Root Scanning during G1 Young GC pauses, which was resolved by caching XStream per class and reducing YGC pauses from seconds to milliseconds.
This article examines how Oracle's G1 garbage collector, the default since JDK 9, outperforms the traditional CMS collector in multi‑core, large‑memory environments through parallelism, space integration, predictive pause models, and real‑world performance testing on Yuewen's licensing service.
This article examines the challenges of GC pauses in low‑latency HBase services, explains ZGC’s fully concurrent architecture and key techniques such as colored pointers and read barriers, and presents experimental comparisons of ZGC and G1 GC using YCSB benchmarks, highlighting latency, throughput and CPU usage differences.
This article explains the design principles, region-based architecture, object allocation strategies, Young and Mixed G1 GC phases, concurrent marking, three‑color marking, and practical tuning parameters for the G1 garbage collector in Java, illustrating concepts with code snippets and diagrams.
This article outlines JD's attempts and explorations in customizing the JDK for HDFS, describing the background, limitations of Oracle JDK 1.8, the adoption of OpenJDK 11 with G1GC, a series of JVM and GC optimizations, performance results, and future development plans.