Three Hot‑Reload Methods for Spring Boot in IDEA – Why JRebel Is the Best

Problem

In large Spring Boot projects, restarting the application after a code change can take 1–2 minutes, which reduces developer productivity.

Evaluated hot‑reload approaches

spring-boot-devtools

IntelliJ IDEA built‑in HotSwap (HowSwap)

JRebel plugin

1. spring-boot-devtools

spring-boot-devtools is the official Spring Boot developer tool that watches the classpath for file changes and triggers an automatic restart.

The automatic restart is relatively slow, so this option is not recommended for large projects.

2. IntelliJ IDEA built‑in HotSwap (HowSwap)

Available only in IntelliJ IDEA Ultimate (not in the Community edition).

2.1 How to use

Set the Spring Boot main class and enable HotSwap in the run configuration.

Run the class in Debug mode and wait for the application to start.

After modifying Java code, click the lower‑left “Hot Load” button to apply the changes instantly.

2.2 Limitations

Only addition of methods or fields is supported; removal is not.

Visibility can be increased but not decreased.

Method signatures must remain unchanged.

Effectively, only modifications inside existing method bodies are hot‑loaded.

3. JRebel plugin (recommended)

JRebel is a widely used hot‑reload plugin that works with both IntelliJ IDEA Ultimate and Community editions.

3.1 Installation

Download version 2022.4.1 from

https://plugins.jetbrains.com/plugin/4441-jrebel-and-xrebel/versions

.

Open Preferences → Plugins , click “Install Plugin from Disk…”, and select the downloaded archive.

Restart IDEA, then open Preferences → JRebel & XRebel and enter the GUID address

https://jrebel.qekang.com/1e67ec1b-122f-4708-87d0-c1995dc0cdaa

, provide any email, and activate JRebel.

Enable “Work Offline” to avoid activation loss due to network issues.

3.2 Usage

Click the “Debug With JRebel” button to start the project with JRebel.

After each Java code change, click the lower‑left “Hot Load” button to apply the changes instantly.