spring-projects/spring-boot · error · ReportableException

File '{}' already exists. Use --force if you want to overwri

Error message

File '{}' already exists. Use --force if you want to overwrite or specify an alternate location.

What it means

Thrown by ProjectGenerator.writeProject when the single-file output target already exists and --force was not supplied. Unlike [93] (per-entry during extraction), this guards the top-level output file path used when writing the project as a single archive.

Source

Thrown at cli/spring-boot-cli/src/main/java/org/springframework/boot/cli/command/init/ProjectGenerator.java:143

						+ "' already exists. Use --force if you want to overwrite or "
						+ "specify an alternate location.");
			}
			if (!entry.isDirectory()) {
				FileCopyUtils.copy(StreamUtils.nonClosing(zipStream), new FileOutputStream(file));
			}
			else {
				file.mkdir();
			}
			zipStream.closeEntry();
			entry = zipStream.getNextEntry();
		}
	}

	private void writeProject(ProjectGenerationResponse entity, String output, boolean overwrite) throws IOException {
		File outputFile = new File(System.getProperty("user.dir"), output);
		if (outputFile.exists()) {
			if (!overwrite) {
				throw new ReportableException(
						"File '" + outputFile.getName() + "' already exists. Use --force if you want to "
								+ "overwrite or specify an alternate location.");
			}
			if (!outputFile.delete()) {
				throw new ReportableException("Failed to delete existing file " + outputFile.getPath());
			}
		}
		byte[] content = entity.getContent();
		Assert.state(content != null, "'content' must not be null");
		FileCopyUtils.copy(content, outputFile);
		Log.info("Content saved to '" + output + "'");
	}

	private void fixExecutableFlag(File dir, String fileName) {
		File f = new File(dir, fileName);
		if (f.exists()) {
			f.setExecutable(true, false);
		}

View on GitHub (pinned to 270dfe353f)

Solutions

Pass --force to overwrite the file
Choose a different --output file name
Delete or rename the existing file first

Example fix

// before
$ spring init --output app.zip  # app.zip exists
// after
$ spring init --output app.zip --force

Defensive patterns

Strategy: validation

Validate before calling

// Before writing, check the output file and decide explicitly.
java.io.File out = new java.io.File(System.getProperty("user.dir"), request.getOutput());
if (out.exists() && !force) {
    throw new IllegalStateException(
        "Output exists: " + out + " - pass --force or pick another name");
}

Try / catch

try {
    generator.generateProject(request, force);
} catch (ReportableException ex) {
    if (ex.getMessage().startsWith("File '") && ex.getMessage().contains("already exists")) {
        Log.error("Output file exists - rerun with --force or a different --output");
    }
    throw ex;
}

Prevention

Use a unique --output name per run (timestamp, project name)
Pass --force only when overwriting intentionally
Clean stale output files in CI between runs

When it happens

Trigger: Writing the project to a file (no --extract) whose path already exists, without --force.

Common situations: Re-running 'spring init --output app.zip' twice; the output file name collides with a pre-existing file.

Related errors

AI-assisted analysis of spring-projects/spring-boot@270dfe353f (2026-08-11). Data as JSON: /api/errors/c286cd2c5ccac5ad. Report an issue: GitHub.