jvm

问题 Running with JVM: java version "1.7.0_79" Java(TM) SE Runtime Environment (build 1.7.0_79-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) OS: CentOS release 6.4 (Final) Jvm Options: -Xmx4g -Xms4g -XX:MaxPermSize=4g -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintClassHistogram -XX:+CMSClassUnloadingEnabled -verbose:gc -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:+DisableExplicitGC Running in an OSGI environment, Aerospike DB, NETTY (NIO) for networking. Ran a weekend longevity

问题 Running with JVM: java version "1.7.0_79" Java(TM) SE Runtime Environment (build 1.7.0_79-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) OS: CentOS release 6.4 (Final) Jvm Options: -Xmx4g -Xms4g -XX:MaxPermSize=4g -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintClassHistogram -XX:+CMSClassUnloadingEnabled -verbose:gc -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:+DisableExplicitGC Running in an OSGI environment, Aerospike DB, NETTY (NIO) for networking. Ran a weekend longevity

问题 Running with JVM: java version "1.7.0_79" Java(TM) SE Runtime Environment (build 1.7.0_79-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) OS: CentOS release 6.4 (Final) Jvm Options: -Xmx4g -Xms4g -XX:MaxPermSize=4g -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintClassHistogram -XX:+CMSClassUnloadingEnabled -verbose:gc -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:+DisableExplicitGC Running in an OSGI environment, Aerospike DB, NETTY (NIO) for networking. Ran a weekend longevity

问题 I have seen and read posts on why System.nanoTime() is slower on some OSes than others, however I have never seen anything to explain the difference I am seeing now. Using JMH, I am running this benchmark. (Note: it uses System.nanoTime() as well) @Benchmark public long systemNanoTime() { return System.nanoTime(); } On Windows 10, this takes ~25 ns. On Centos 7, Linux 3.10 it is measured as taking ~10293 ns. This is on the same machine, Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz Is there an

问题 I've almost tried everything including: Change system region and language to be 'english US' Use Locale.setDefaultLocale() Pass in JVM arguments It prints out: Default locale is : en_US BUT my application is still throwing exception with Chinese exception message Does this have anything to do with Spring? (my app is based on Spring, but there is no locale-related config whatsover, so it should be just using whatever is default) Can anyone help me with this? UPDATE: I'm basically getting a

问题 I've almost tried everything including: Change system region and language to be 'english US' Use Locale.setDefaultLocale() Pass in JVM arguments It prints out: Default locale is : en_US BUT my application is still throwing exception with Chinese exception message Does this have anything to do with Spring? (my app is based on Spring, but there is no locale-related config whatsover, so it should be just using whatever is default) Can anyone help me with this? UPDATE: I'm basically getting a

问题 I've almost tried everything including: Change system region and language to be 'english US' Use Locale.setDefaultLocale() Pass in JVM arguments It prints out: Default locale is : en_US BUT my application is still throwing exception with Chinese exception message Does this have anything to do with Spring? (my app is based on Spring, but there is no locale-related config whatsover, so it should be just using whatever is default) Can anyone help me with this? UPDATE: I'm basically getting a

问题 Im on Linux and my Java application is not intended to be portable. I'm looking for a way to identify a file uniquely in Java. I can make use of statfs syscall since the pair (f_fsid, ino) uniquely identifies a file (not only across a file system) as specified here: http://man7.org/linux/man-pages/man2/statfs.2.html The question is if it is possible extract fsid from Java directly so I can avoid writing JNI function? inode can be extracted with NIO , but how about fsid? inode and fsid comes

问题 Im on Linux and my Java application is not intended to be portable. I'm looking for a way to identify a file uniquely in Java. I can make use of statfs syscall since the pair (f_fsid, ino) uniquely identifies a file (not only across a file system) as specified here: http://man7.org/linux/man-pages/man2/statfs.2.html The question is if it is possible extract fsid from Java directly so I can avoid writing JNI function? inode can be extracted with NIO , but how about fsid? inode and fsid comes

问题 I heard an associate say: JVM garbage collection times increase exponentially with JVM size. This is because the tree of references is a function of the amount of the amount of objects to allocate - and gets exponentially harder to traverse the tree as the number of objects get bigger. This sounded right. I heard another associate say: JVM garbage collection on the same machine is linear. Given an 8GB JVM split in two 4G JVMs on the same machine (via microservices) will have the same garbage