Error drawing CAPTCHA in springBoot!

1, springBoot version 1.5.9
2, jdk version 1.8
problem description:

http://localhost:35620/api/admin/login
2018-06-02 00:04:31.739 |-INFO  [XNIO-2 task-1] org.thymeleaf.TemplateEngine [825] -| [THYMELEAF] INITIALIZING TEMPLATE ENGINE
2018-06-02 00:04:31.849 |-INFO  [XNIO-2 task-1] org.thymeleaf.templateresolver.AbstractTemplateResolver [99] -| [THYMELEAF] INITIALIZING TEMPLATE RESOLVER: org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver
2018-06-02 00:04:31.850 |-INFO  [XNIO-2 task-1] org.thymeleaf.templateresolver.AbstractTemplateResolver [110] -| [THYMELEAF] TEMPLATE RESOLVER INITIALIZED OK
2018-06-02 00:04:31.851 |-INFO  [XNIO-2 task-1] org.thymeleaf.messageresolver.AbstractMessageResolver [72] -| [THYMELEAF] INITIALIZING MESSAGE RESOLVER: org.thymeleaf.spring4.messageresolver.SpringMessageResolver
2018-06-02 00:04:31.851 |-INFO  [XNIO-2 task-1] org.thymeleaf.messageresolver.AbstractMessageResolver [78] -| [THYMELEAF] MESSAGE RESOLVER INITIALIZED OK
2018-06-02 00:04:31.862 |-INFO  [XNIO-2 task-1] org.thymeleaf.TemplateEngine.CONFIG [123] -| [THYMELEAF] TEMPLATE ENGINE CONFIGURATION:
[THYMELEAF] * Cache Factory implementation: org.thymeleaf.cache.StandardCacheManager
[THYMELEAF] * Template modes:
[THYMELEAF]     * XHTML
[THYMELEAF]     * HTML5
[THYMELEAF]     * VALIDXML
[THYMELEAF]     * VALIDXHTML
[THYMELEAF]     * LEGACYHTML5
[THYMELEAF]     * XML
[THYMELEAF] * Template resolvers (in order):
[THYMELEAF]     * org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver
[THYMELEAF] * Message resolvers (in order):
[THYMELEAF]     * org.thymeleaf.spring4.messageresolver.SpringMessageResolver
[THYMELEAF] * Dialect [1 of 2]: org.thymeleaf.spring4.dialect.SpringStandardDialect
[THYMELEAF]     * Prefix: "th"
[THYMELEAF] * Dialect [2 of 2]: nz.net.ultraq.thymeleaf.LayoutDialect
[THYMELEAF]     * Prefix: "layout"
[THYMELEAF] TEMPLATE ENGINE CONFIGURED OK
2018-06-02 00:04:31.863 |-INFO  [XNIO-2 task-1] org.thymeleaf.TemplateEngine [838] -| [THYMELEAF] TEMPLATE ENGINE INITIALIZED
http://localhost:35620/api/admin/verify-code
http://localhost:35620/api/error

visits the home page and requests that the CAPTCHA be drawn, but when drawing, the http://localhost:35620/api/error is output. Under windows, you will not jump to the error page. You can log in successfully, deploy to linux, and jump to the error page immediately.

when I debug, I find that after executing

 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
An error occurs when

is used in this statement, but the cause of the error is not at all clear.

Note: embedded servers use undertow, not tomcat

Mar.16,2021

is a little disgusting < del > I configured the error page. When publishing to the online environment, because the absolute path is used when jumping to the home page. For example, modelAndView.setViewName ("/ login"). Online environments should use relative paths, such as modelAndView.setViewName ("login"). This is the right one. Then today I rebooted and found that the console did not print localhost/api/error. Speechless < / del > ~

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b31b02-2b2ff.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b31b02-2b2ff.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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