[garbage-collection] How to redirect verbose garbage collection output to a file?

How do I redirect verbose garbage collection output to a file? Sun’s website shows an example for Unix but it doesn't work for Windows.

If in addition you want to pipe the output to a separate file, you can do:

On a Sun JVM:

-Xloggc:C:\whereever\jvm.log -verbose:gc -XX:+PrintGCDateStamps

ON an IBM JVM:

-Xverbosegclog:C:\whereever\jvm.log 

Java 9 & Unified JVM Logging

JEP 158 introduces a common logging system for all components of the JVM which will change (and IMO simplify) how logging works with GC. JEP 158 added a new command-line option to control logging from all components of the JVM:

-Xlog

For example, the following option:

-Xlog:gc

will log messages tagged with gc tag using info level to stdout. Or this one:

-Xlog:gc=debug:file=gc.txt:none

would log messages tagged with gc tag using debug level to a file called gc.txt with no decorations. For more detailed discussion, you can checkout the examples in the JEP page.

To add to the above answers, there's a good article: Useful JVM Flags – Part 8 (GC Logging) by Patrick Peschlow.

A brief excerpt:

The flag -XX:+PrintGC (or the alias -verbose:gc) activates the “simple” GC logging mode

By default the GC log is written to stdout. With -Xloggc:<file> we may instead specify an output file. Note that this flag implicitly sets -XX:+PrintGC and -XX:+PrintGCTimeStamps as well.

If we use -XX:+PrintGCDetails instead of -XX:+PrintGC, we activate the “detailed” GC logging mode which differs depending on the GC algorithm used.

With -XX:+PrintGCTimeStamps a timestamp reflecting the real time passed in seconds since JVM start is added to every line.

If we specify -XX:+PrintGCDateStamps each line starts with the absolute date and time.