G1 Collector

  1. Minor收集:Minor GC总是在不能为新的对象分配空间的时候触发, 例如 Eden区满了
  2. Mayor收集：
  3. concurrent: 并发, 多个线程协同做同一件事情(有状态)
  4. parallel: 并行, 多个线程各做各的事情(互相间无共享状态)

JDK 8 --- Internal Strings??关闭String池就是从JDK7到JDK8的一个过渡

java –Xmx1G –Xms1G –XX:+UseG1GC –XX:+PrintGCDetails –XX:+PrintGCTimeStamps GCTestBench

We then tried using the G1 GC. We even added the -XX:+UseStringDeduplication argument, which the G1 collector can use to eliminate storing duplicates of Strings.

G1 garbage collector log analyzer

Memory Analyzer

  1. The dominator tree allows you to identify the largest memory graphs. An Object X is said to dominate an Object Y if every path from the Root to Y must pass through X.
  2. retained heap column of Histogram report _shows the sum of the shallow heap size of all objects that would be removed when this object is garbage collected. It shows which class is taking up the majority of the memory.

Books

  1. Addison Java Performance Companion 2016

References

  1. G1垃圾收集器入门
  2. JVM 垃圾回收 Minor gc vs Major gc vs Full gc
  3. Java Garbage Collection handbook
  4. Oracle Document: Getting Started with the G1 Garbage Collector
  5. 深入理解G1垃圾收集器
  6. G1垃圾回收器中的字符串去重(Java 8 Update 20)
  7. What is garbage collection visualization?
  8. Using R to analyze Java G1 garbage collector log files
  9. Garbage Collector Log Analysers
  10. 10 Tips for using the Eclipse Memory Analyzer

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