--- title: Spring Boot 4 Breaks Null Into Int (Jackson 3 Default) description: In Spring Boot 4, Jackson 3 changes a default. Sending null to a primitive int now returns a 400 instead of quietly becoming zero. No test caught it, so if... canonical: https://daily.dev/posts/spring-boot-4-breaks-null-into-int-jackson-3-default--gpaaatorj twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Spring Boot 4 Breaks Null Into Int (Jackson 3 Default) | daily.dev og:description: In Spring Boot 4, Jackson 3 changes a default. Sending null to a primitive int now returns a 400 instead of quietly becoming zero. No test caught it, so if... og:url: https://daily.dev/posts/spring-boot-4-breaks-null-into-int-jackson-3-default--gpaaatorj og:image: https://api.daily.dev/og/posts/gpaAAtoRJ.png og:image:alt: Spring Boot 4 Breaks Null Into Int (Jackson 3 Default) og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Spring Boot 4 Breaks Null Into Int (Jackson 3 Default) **[Dan Vega](https://daily.dev/sources/dan-vega)** · 1 min read · 0 upvotes · 0 comments ## Summary In Spring Boot 4, Jackson 3 changes a default. Sending null to a primitive int now returns a 400 instead of quietly becoming zero. No test caught it, so if clients send nulls today, they break after the upgrade. #SpringBoot #Jackson #Java #SpringBoot4 ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#java](https://daily.dev/tags/java), [#spring](https://daily.dev/tags/spring) [View this post on daily.dev](https://daily.dev/posts/spring-boot-4-breaks-null-into-int-jackson-3-default--gpaaatorj) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Spring Boot 4 Breaks Null Into Int (Jackson 3 Default)","url":"https://daily.dev/posts/spring-boot-4-breaks-null-into-int-jackson-3-default--gpaaatorj","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/spring-boot-4-breaks-null-into-int-jackson-3-default--gpaaatorj"},"datePublished":"2026-10-02T16:02:41.748Z","dateModified":"2026-10-02T17:49:50.209Z","description":"In Spring Boot 4, Jackson 3 changes a default. 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