A Java IDE that stays under 400 MB while the rest bloat

What it does

Lithe is a cross-platform IDE that targets Java and Spring Boot projects. It handles the usual suspects—editing, navigation, Maven, breakpoint debugging, Git diff review, local history, and database connections—while keeping baseline memory around 300–400 MB. Heavy helpers like language servers, terminals, and debuggers stay offstage until you actually call them.

The interesting bit

The architecture splits native UI from shared logic: macOS uses SwiftUI/AppKit, Windows uses React/Tauri, and both talk to a Rust core through JSON contracts. It is a pragmatic bet that the modern IDE is less about writing every line and more about browsing, running, and reviewing what AI already generated.

Key highlights

• Baseline memory footprint of roughly 300–400 MB after opening a regular project, with language servers and debuggers launching on demand.
• Native macOS (SwiftUI/AppKit) and Windows (React/Tauri) frontends backed by a shared Rust core that handles deterministic commands and contracts.
• Per-language service toggles, multi-line editor tabs, a database workspace, and automatic entry-point detection for Spring Boot, Maven, Gradle, npm, Cargo, Go, Python, and more.
• AI-assisted commit-message generation with customizable formats and rich Markdown preview.
• An in-app memory monitor so you can watch the footprint grow as you summon heavier services.

Caveats

• macOS is the current reference implementation; the Windows build is an independent React/Tauri port that shares the Rust core but may differ in native integration.
• Manually downloaded macOS releases can trigger Apple’s malware verification warning because the app may not yet be notarized, forcing a manual security override.
• The 300–400 MB figure is a baseline, not a ceiling; actual usage climbs once you start language servers, debuggers, and database helpers.

Verdict

Spring Boot and Java developers who want a fast, low-memory environment to navigate and run AI-assisted code should take a look. If you rely on IntelliJ’s full plugin marketplace or you work outside the Java-centric toolchain, this is not your replacement.