skylot/jadx · critical · RuntimeException

Failed to create temp root directory

Error message

Failed to create temp root directory

What it means

Thrown by JadxTempFiles (static init) as a RuntimeException wrapping any exception during temp root directory creation. It honors JADX_TMP_DIR (creating a temp instance dir under it) or falls back to the system temp dir; any failure is wrapped here.

Source

Thrown at jadx-commons/jadx-app-commons/src/main/java/jadx/commons/app/JadxTempFiles.java:30

	public static Path getTempRootDir() {
		return TEMP_ROOT_DIR;
	}

	private static Path createTempRootDir() {
		try {
			String jadxTmpDir = System.getenv("JADX_TMP_DIR");
			Path dir;
			if (jadxTmpDir != null) {
				Path customTmpRootDir = Paths.get(jadxTmpDir);
				Files.createDirectories(customTmpRootDir);
				dir = Files.createTempDirectory(customTmpRootDir, JADX_TMP_INSTANCE_PREFIX);
			} else {
				dir = Files.createTempDirectory(JADX_TMP_INSTANCE_PREFIX);
			}
			dir.toFile().deleteOnExit();
			return dir;
		} catch (Exception e) {
			throw new RuntimeException("Failed to create temp root directory", e);
		}
	}
}

View on GitHub (pinned to e738a26571)

Solutions

1. Point JADX_TMP_DIR to a writable absolute directory.
2. Ensure java.io.tmpdir (system temp) is writable.
3. Free space on the temp filesystem.
4. Check container mount options for /tmp (remove ro/noexec if present).

Example fix

// before (read-only /tmp in container)
jadx input.apk
// after
JADX_TMP_DIR=/var/tmp/jadx jadx input.apk

String t = System.getenv("JADX_TMP_DIR");
if (t != null) {
    Path p = Paths.get(t);
    Files.createDirectories(p);
    if (!Files.isWritable(p)) throw new IllegalStateException("JADX_TMP_DIR not writable: " + t);
} else {
    Path sysTmp = Paths.get(System.getProperty("java.io.tmpdir"));
    if (!Files.isWritable(sysTmp)) throw new IllegalStateException("System temp not writable: " + sysTmp);
}

public static boolean tmpWritable() {
    try {
        Path t = System.getenv("JADX_TMP_DIR") != null ? Paths.get(System.getenv("JADX_TMP_DIR")) : Paths.get(System.getProperty("java.io.tmpdir"));
        Files.createDirectories(t);
        return Files.isWritable(t);
    } catch (IOException e) { return false; }
}

// Fires during static init of JadxTempFiles
try {
    Class.forName("jadx.commons.app.JadxTempFiles");
} catch (ExceptionInInitializerError e) {
    Throwable c = e.getCause();
    if (c instanceof RuntimeException && c.getMessage().equals("Failed to create temp root directory")) {
        System.err.println("Set JADX_TMP_DIR to a writable dir. Cause: " + c.getCause());
        System.exit(1);
    }
    throw e;
}

When it happens

Trigger: JADX_TMP_DIR set to a path where createDirectories or createTempDirectory fails; the system java.io.tmpdir is not writable; permission denied; disk full during init.

Common situations: Running jadx in a container/CI where /tmp is read-only or mounted with noexec/nodev; JADX_TMP_DIR pointing to a non-existent parent that cannot be created; temp filesystem full.

Related errors

• Failed to init common directories
• Failed to save JSON file: {}
• Failed to save JSON file: {}
• {}
• Failed to open zip: {}

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/d3d006e475a915d5. Report an issue: GitHub.