Unified logging for JVM

The main components of JVM include the following:

• Classloader
• JVM memory where the runtime data is stored; it is broken down into the following areas:
  • Stack area
  • Method area
  • Heap area
  • PC registers
  • Native method stack
• Execution engine, which consists of the following parts:
  • Interpreter
  • The JIT compiler
  • Garbage collection
  • Native method interface JNI
  • Native method library

The log message of all these components can now be captured and analyzed using unified logging, turned on by the -Xlog option.

The main features of the new logging system are as follows:

• Usage of the log levels—trace, debug, info, warning, error
• Message tags that identify the JVM component, action, or message of a specific interest
• Three output types—stdout, stderr, and file
• The enforcement of the one-message-per-line limit

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