{
  "id": 6895502,
  "title": "Fat jar vs layered jar; DevTools",
  "url": "https://urgent.news/2026/09/12/fat-jar-vs-layered-jar-devtools",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-12T08:45:30.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/ankit_verma_e2fa7fb2aa95d/fat-jar-vs-layered-jar-devtools-5ajc"
  },
  "original_language": "en",
  "account": "When you create a Spring Boot service, a single command compiles it into a runnable file, such as \"java -jar app.jar\". This file contains the web server, classpath, and application server all in one. The rest of this report will examine the contents of this file, why it is structured this way, and the two packaging options that determine how the app runs and ships: the fat jar and the layered jar. At the end, we'll discuss DevTools, which speeds up the development process.",
  "summary": "Why your Spring Boot app is one runnable file You finish a Spring Boot service, run a single command, and a full web server starts up: java -jar app.jar No Tomcat to install first. No classpath to spell out by hand. No WEB-INF folder dropped into a separate application server. One file, one command, a running app that answers HTTP on a port. That single file is what this article is about. We will…",
  "key_points": [
    "Spring Boot service compiled into single runnable file",
    "Fat jar and layered jar are two packaging options",
    "DevTools speeds up development process"
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}