quarkusio/quarkus · error · GradleException

Failed to copy %s to %s

Error message

Failed to copy %s to %s

What it means

For ordinary jar dependencies, jarDependencies copies each jar into the dependency cache with Files.copy using COPY_ATTRIBUTES. If the copy fails with IOException the build fails with this GradleException naming source and target. Commonly a lock, permission, or disk-space problem on either side of the copy.

Source

Thrown at devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/QuarkusBuildDependencies.java:211

                        if (!Files.exists(target)) {
                            getLogger().debug("Dependency {} : copying {} to {}",
                                    dep.toGACTVString(),
                                    p, target);
                            if (Files.isDirectory(p)) {
                                // This case can happen when we are building a jar from inside the Quarkus repository
                                // and Quarkus Bootstrap's localProjectDiscovery has been set to true. In such a case
                                // the non-jar dependencies are the Quarkus dependencies picked up on the file system
                                try {
                                    ZipUtils.zip(p, target);
                                } catch (IOException e) {
                                    throw new GradleException(
                                            String.format("Failed to archive classes at %s into %s", p, target), e);
                                }
                            } else {
                                try {
                                    Files.copy(p, target, StandardCopyOption.COPY_ATTRIBUTES);
                                } catch (IOException e) {
                                    throw new GradleException(String.format("Failed to copy %s to %s", p, target), e);
                                }
                            }
                        }
                    });
                })
                .collect(Collectors.toMap(Map.Entry::getKey, depAndTarget -> 1, Integer::sum))
                .forEach((path, count) -> getLogger().info("Copied {} files into {}", count, path));
    }

    private static Set<ArtifactKey> dependenciesListToArtifactKeySet(String optionalDependenciesProp) {
        return Arrays.stream(optionalDependenciesProp.split(","))
                .map(String::trim)
                .filter(gact -> !gact.isEmpty())
                .map(ArtifactKey::fromString)
                .collect(Collectors.toSet());
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Stop running Quarkus dev/lock-holding processes and other Gradle daemons (./gradlew --stop), then rebuild
2. Verify disk space and write permissions on the dependency output directory
3. Check the source jar exists and is readable; re-download it by deleting it from the local cache
4. Run ./gradlew clean quarkusBuild to start from a clean layout

Example fix

// shell-side remedy
./gradlew --stop
rm -rf build/quarkus-build/dependencies
./gradlew quarkusBuild

File depDir = new File("build/quarkus-build/dependencies");
if (depDir.exists() && !depDir.canWrite())
    throw new IllegalStateException("Dependency output dir not writable: " + depDir);

try {
    ./gradlew quarkusBuild
} catch (GradleException e) {
    if (e.message?.startsWith("Failed to copy") && e.message.contains(" to ")) {
        "./gradlew --stop".execute().waitFor();
        deleteDir(new File("build/quarkus-build/dependencies")); retry();
    } else { throw e; }
}

When it happens

Trigger: Files.copy(p, target, COPY_ATTRIBUTES) throws IOException while copying a dependency jar into the build dependency directory during fast-jar/legacy-jar dependency assembly.

Common situations: Jar locked by a running dev-mode process or IDE (Windows); read-only local repository or output directory; disk full; source jar deleted by a concurrent Gradle daemon build.

Related errors

• Unable to copy extension file for: ${extension}
• Failed to load extension description + path
• Failed to create directories in %s
• Failed to load + pomPropsPath + from the classpath
• Failed to locate io.quarkus:quarkus-core-deployment on the a

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/e73395548604f2fd. Report an issue: GitHub.