= Capturing Standard Output/Error

The JUnit Platform provides opt-in support for capturing output printed to `System.out`
and `System.err`. To enable it, set the `junit.platform.output.capture.stdout` and/or
`junit.platform.output.capture.stderr` xref:running-tests/configuration-parameters.adoc[configuration
parameter] to `true`. In addition, you may configure the maximum number of buffered bytes
to be used per executed test or container using `junit.platform.output.capture.maxBuffer`.

If enabled, the JUnit Platform captures the corresponding output and publishes it as a
report entry using the `stdout` or `stderr` keys to all registered
`{TestExecutionListener}` instances immediately before reporting the test or container as
finished.

Please note that the captured output will only contain output emitted by the thread that
was used to execute a container or test. Any output by other threads will be omitted
because particularly when
xref:writing-tests/parallel-execution.adoc[executing tests in parallel] it would be impossible
to attribute it to a specific test or container.
