JCode

A native Android IDE with an embedded Linux runtime — build, run, and edit real projects entirely on-device.

---

JCode is an Android IDE written in Kotlin + Jetpack Compose, with C++/NDK for the performance-critical subsystems (editor buffer, VT terminal, parsers). It embeds a self-contained Linux environment via bundled proot — runtimes, SDKs, compilers, and language servers live in an app-managed Ubuntu 24.04 / 26.04 LTS rootfs in app-private storage. No Termux dependency, no root.

Features

• Editor — an in-house Canvas + IME code editor with a native piece-tree buffer, syntax colouring, LSP + Dev Pack completions, snippets, multi-tab editing, selection handles, word wrap, Save (Ctrl+S / button / dirty indicator), and auto-reload of unmodified files changed on disk.
• Language intelligence — language servers run inside the selected distro and provide diagnostics, completions, Go to Definition, Find References, Rename Symbol, and document formatting. Missing servers can be installed from the editor; their lifecycle follows the open project and documents.
• Terminals — real PTY sessions through proot that survive app backgrounding, with full xterm/VT support (mouse reporting, SGR, alt-screen), in-place progress redraw, and a code/jcode command to open files in the editor.
• Build & Run — per-project .jcode/run.yaml; multi-terminal dev setups (e.g. an ASP.NET Core API + a Vite dev server side by side); a read-only Output log teed from the run terminals; and ready-port polling into a web preview.
• Debugging — a Debug Adapter Protocol (DAP) client with gutter breakpoints, stepping, call stack, variables, and a debug console. Python (debugpy) and Java are device-verified under proot.
• Android app sandbox — build an APK and run it inside an editor tab, with a device-side ADB bridge and JDWP debugging against the same device.
• Source Control — an extension-hosted Git panel (status, stage, commit, branch, diffs) in the left drawer, plus live VCS status decorations in the Explorer. Git itself runs inside the distro.
• Search — project-wide find (ripgrep-backed) with Content / File-name / Current-document scopes and a Kotlin fallback when the native search library is unavailable.
• Problems — an Issues panel and status-bar count fed by a shared diagnostics bus (language servers, config-file errors, and syntax checks), with in-gutter squiggles.
• Extensions — a marketplace of Ed25519-verified .jext packages (Dev Packs, project templates, and manager UIs), plus .vsix import for the supported WebView slice of the VS Code API.
• Toolchains — a unified manager for installing and updating SDKs, language servers, debug engines, database clients, and developer tools per distro.
• Embedded Linux — bundled proot binaries for arm64-v8a and x86_64, with downloaded ARM64 Ubuntu 24.04 / 26.04 LTS profiles; apt-managed toolchains; project directories bind-mounted into the distro.

Build

Requirements: JDK 21, the Android SDK (compileSdk 36), NDK r27c (27.2.12479018), and CMake 3.28.3. minSdk/targetSdk 33 (Android 13+). The repository currently uses AGP 8.13.0, Kotlin 2.2.20, and the Gradle 8.14.3 wrapper.

git clone https://github.com/blamspotdev/j-code-android.git
cd j-code-android
./gradlew :app:assembleDebug      # → app/build/outputs/apk/debug/app-debug.apk

Windows note: build from a short path (e.g. X:\jc). Deep checkout paths can exceed the Win32 MAX_PATH limit during the native (tree-sitter) build.

The first native build needs network access because CMake fetches pinned upstream dependencies. Release builds and signing are documented in the build and release specification.

Architecture

A multi-module Gradle project:

:app            integration layer + the JCode shell
:core:*         editor, buffer, term, distro, lsp, debug, search, config, diagnostics,
                design, fs, treesitter, resource, and compatibility stubs
:feature:*      explorer, editor-pane, terminal-pane, scm, debug, problems, search,
                settings, sdk-manager, lsp-manager, marketplace, onboarding
:native:*       proot, vt (terminal), pty, tree-sitter, buffer (piece tree),
                libgit2, ripgrep-ffi, wasmtime-ffi, editor-render, …

Module rule: :core:* never depends on :feature:*; :feature:* depends only on :core:*; :app depends on everything. All buffer writes flow through EditorState.applyEdit on a single-threaded dispatcher; JNI/native handles are wrapped as AutoCloseable + Cleaner.

Documentation

Full as-built engineering specifications live in docs/specifications/ — architecture, module contracts, wire protocols, on-disk formats, and build/release details. Each document closes with a "Known gaps" section recording what is stubbed, unwired or limited in that subsystem, so the caveat sits beside the thing it qualifies.

Extensions

Dev Packs, templates, and (later) theme / icon sets install from the JCode marketplace as verified .jext packages. To build your own, see the marketplace's CREATING-EXTENSIONS.md and the j-code-make-tools CLI.

License

Licensed under the MIT License. © 2026 blamspotdev (Janrick Samorin). You're free to use, modify, and redistribute it under the MIT terms. Contributions are covered by CONTRIBUTING.md; third-party components and their licenses are listed in THIRD-PARTY-NOTICES.md.