Cgroup Metrics – now available in Javacore

  Eclipse OpenJ9 can now provide Linux cgroup information as part of a Java dump file, commonly known as a javacore. This can be very handy to debug clearly by having the information about the environment in which JVM is running and if JVM is aware of the limits imposed by the environment etc. In…

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Introducing option builder tools for -Xdump and -Xtrace

OpenJ9 provides some powerful command line options for troubleshooting problems with Java applications at runtime. – The -Xdump option is used to control the use of dump agents, which produce dump files such as Java dumps, heap dumps, and system (core) dumps. – The -Xtrace option can be used to trace Java applications, methods, and…

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Gather Diagnostic Data from your Containerized Java Application on the fly

Ever tried to debug Java issues in Docker containers? How does one go about doing it? This article talks about one mechanism in Eclipse OpenJ9 that makes it a lot easier to obtain debug information from Java applications running inside Docker containers. A running OpenJ9 JVM includes mechanisms for producing different types of diagnostic data when events of interest occur. In general, the…

Reading Verbose JIT Logs

This article is the first in a series that provides useful information for analyzing JIT compiler operations. In this first article I’ll explain how to obtain JIT verbose logs and the basics for how to read them. A JIT verbose log is a summary of what methods were compiled by the JIT and some of…