Jetty 12.1.4 Startup Time Optimization

[Panduchunkz]

Jetty Version
12.1.4

Jetty Environment
ee11

Java Version
Java 25 (LTS)

Question
I had deployed more than 15 WAR files which was compiled by the latest java version and observed that overall startup time (includes all the annotation scanning and Xml Configurations) of latest jetty took ~1min which is greater than the Old Jetty 9 WAR loading. Kindly suggest me the best solutions to improve the performance.

[joakime]

The quickstart module should help.

See: https://jetty.org/docs/jetty/12.1/operations-guide/quickstart/index.html

[Panduchunkz]

Already added the quickstart module with parameter value of "jetty.quickstart.mode=AUTO" but no improvements. If you have any sample reference xml file for quickstart configuration rather than this AUTO mode. Kindly send it.

[joakime]

A typical setup is to have the GENERATE mode done during development time.

Then the AUTO mode setup for runtime.

[Panduchunkz]

When I am trying to use GENERATE mode, it shows a log as xml file was generated in non- persistent location. For more clarity, see the attached log messages.

2026-01-16 11:47:30.021:INFO :oeje11q.QuickStartGeneratorConfiguration:main: Generated C:\Windows\Temp\jetty-0_0_0_0-1130-nts_war-_nts-_httpConnector-13211604955399907462\webapp\WEB-INF\qucikstart-web.xml
2026-01-16 11:47:30.022:WARN :oeje11q.QuickStartGeneratorConfiguration:main: Generated to non persistent location: C:\Windows\Temp\jetty-0_0_0_0-1130-nts_war-_nts-_httpConnector-13211604955399907462\webapp\WEB-INF\quickstart-web.xml

After this, the server was stopped by the GENERATE mode. Also, the generated xml files were deleted. Then also i noted that, AUTO mode doesn't make any impact in the startup slowness.

[lachlan-roberts]

Looks like an issue with an unpacked WAR file. See the last paragraph of the quickstart docs

Note that by default Jetty unpacks to a temporary location which is not reused between executions. You must either specify the directory where to unpack, or make a work directory in your $JETTY_BASE to ensure the unpacked war is preserved and reused across restarts.

[Panduchunkz]

Unpacking war in the specific location gets deleted once the server is stopped. Jetty 9 has no issues like this. But i am facing this in jetty 12 only. Is there any property to disable the temp file cleanup by jetty automatically?

[joakime]

Some options...

The Jetty specific APIs.

• Use WebAppContext.setTempDirectory(File) to set the location.
• Use WebAppContext.setTempDirectoryPersistent(boolean) to prevent the directory from being cleaned out between runs.

The Jakarta Servlet APIs.

• Use the Jakarta ServletContext attribute jakarta.servlet.ServletContext.TEMPDIR to set the java.io.File location before the webapp starts.