metaspace

How to get Java8 Metaspace dump (not heap dump)

由 狂风中的少年 提交于 2019-11-29 11:46:11
问题 Are there any tools that are able to get Metaspace dump from a Java8 hotspot vm ? 回答1: It seems you encounter a class loading leak. Use jmap -clstats PID to dump class loader statistics; jcmd PID GC.class_stats to print the detailed information about memory usage of each loaded class. The latter requires -XX:+UnlockDiagnosticVMOptions . The heap dump will also help, because each class in the Metaspace has a corresponding java.lang.Class instance in the heap. 来源： https://stackoverflow.com

java8 “java.lang.OutOfMemoryError: Metaspace”

由 。_饼干妹妹 提交于 2019-11-28 20:21:58
After switching our java application (services running on Tomcat) JRE from Java 7 to Java 8, we started to see java.lang.OutOfMemoryError: Metaspace after running a few days with high traffic volume. Heap usage was OK. Metaspace jumps after sometime when the same code flow was executed during performance testing. What could be possible causes of the metaspace memory issue? Current settings is: -server -Xms8g -Xmx8g -XX:MaxMetaspaceSize=3200m -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:MaxGCPauseMillis=1000 -XX:+DisableExplicitGC -XX:+PrintGCDetails -XX:-UseAdaptiveSizePolicy -XX:SurvivorRatio

Understanding metaspace line in JVM heap printout

由 女生的网名这么多〃 提交于 2019-11-28 05:59:18
In a Java 8 heap printout, you may see a line that looks like: Metaspace used 2425K, capacity 4498K, committed 4864K, reserved 1056768K https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/considerations.html tries to explain the line: In the line beginning with Metaspace, the used value is the amount of space used for loaded classes. The capacity value is the space available for metadata in currently allocated chunks. The committed value is the amount of space available for chunks. The reserved value is the amount of space reserved (but not necessarily committed) for metadata.

Java memory areas in java 8

由 ⅰ亾dé卋堺 提交于 2019-11-28 05:48:40
问题 I have read a lot about java memory areas, but looks like it is just a mess. Mostly due to the introduction of a new MetaSpace area instead of PermGen in java8. And there are questions now: What areas does the heap include in java8+ ? Where the static methods and variables are stored before java8 and java8+ ? Does the MetaSpace store anything except class meta-data info ? Does the structure of memory areas depend on the implementation of JVM ? Thank you for your answers. 回答1: Does the

What is the difference between PermGen and Metaspace?

由 落爺英雄遲暮 提交于 2019-11-26 23:20:36
Until Java 7 there was an area in JVM memory called PermGen , where JVM used to keep its classes. In Java 8 it was removed and replaced by area called Metaspace . What are the most important differences between PermGen and Metaspace? The only difference I know is that java.lang.OutOfMemoryError: PermGen space can no longer be thrown and the VM parameter MaxPermSize is ignored. Mattias Jiderhamn The main difference from a user perspective - which I think the previous answer does not stress enough - is that Metaspace by default auto increases its size (up to what the underlying OS provides),

Understanding metaspace line in JVM heap printout

由 大城市里の小女人 提交于 2019-11-26 15:49:19
问题 In a Java 8 heap printout, you may see a line that looks like: Metaspace used 2425K, capacity 4498K, committed 4864K, reserved 1056768K https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/considerations.html tries to explain the line: In the line beginning with Metaspace, the used value is the amount of space used for loaded classes. The capacity value is the space available for metadata in currently allocated chunks. The committed value is the amount of space available for
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