spring-projects/spring-boot · error · GradleException

Failed to read '{}'

Error message

Failed to read '{}'

What it means

Thrown by ApplicationPluginAction.loadResource() when reading the bundled start-script templates (/unixStartScript.txt, /windowsStartScript.txt) from the plugin jar's classpath fails with IOException, wrapped as a GradleException. These templates are required to generate bootStartScripts for the 'boot' distribution. The plugin ships them inside its own jar, so a read failure means the plugin artifact is damaged or its classloader is misconfigured.

Source

Thrown at build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/ApplicationPluginAction.java:125

	}

	@Override
	public Class<? extends Plugin<Project>> getPluginClass() {
		return ApplicationPlugin.class;
	}

	private String loadResource(String name) {
		try (InputStreamReader reader = new InputStreamReader(getResourceAsStream(name))) {
			char[] buffer = new char[4096];
			int read;
			StringWriter writer = new StringWriter();
			while ((read = reader.read(buffer)) > 0) {
				writer.write(buffer, 0, read);
			}
			return writer.toString();
		}
		catch (IOException ex) {
			throw new GradleException("Failed to read '" + name + "'", ex);
		}
	}

	private InputStream getResourceAsStream(String name) {
		InputStream stream = getClass().getResourceAsStream(name);
		Assert.state(stream != null, "Resource '%s' not found'".formatted(name));
		return stream;
	}

	private void configureFilePermissions(CopySpec copySpec, int mode) {
		if (GradleVersion.current().compareTo(GradleVersion.version("8.3")) >= 0) {
			copySpec.filePermissions((filePermissions) -> filePermissions.unix(Integer.toString(mode, 8)));
		}
		else {
			configureFileMode(copySpec, mode);
		}
	}

View on GitHub (pinned to 5b2dbdbb8b)

Solutions

1. Clear the Gradle cache for the plugin and re-resolve: rm -rf ~/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-gradle-plugin then refresh dependencies.
2. Verify the plugin jar is intact: list the archive contents (jar tf) and confirm /unixStartScript.txt and /windowsStartScript.txt are present.
3. Remove any shadow/shade/dependency-reduce tricks that relocate or strip resources from the spring-boot-gradle-plugin; load it as a normal classpath dependency.
4. Pin an uncorrupted plugin version in your buildscript/plugins block and run with --refresh-dependencies.

Example fix

// build.gradle.kts — force a clean re-download of the plugin
// then re-sync
// shell:
//   ./gradlew --refresh-dependencies build

// Verify the bundled templates exist in the resolved plugin jar before applying
import java.util.jar.JarFile

fun pluginTemplatesIntact(pluginJar: java.io.File): Boolean {
    JarFile(pluginJar).use { jar ->
        return jar.getJarEntry("unixStartScript.txt") != null &&
               jar.getJarEntry("windowsStartScript.txt") != null
    }
}

try {
    project.pluginManager.apply("org.springframework.boot")
} catch (ex: org.gradle.api.GradleException) {
    if (ex.message?.startsWith("Failed to read '") == true) {
        logger.error("Spring Boot plugin resources are missing/corrupt. " +
            "Clear ~/.gradle/caches and re-resolve the plugin.")
    }
    throw ex
}

When it happens

Trigger: Applying the Gradle 'application' plugin alongside Spring Boot triggers ApplicationPluginAction.execute(), which calls loadResource() for unixStartScript.txt and windowsStartScript.txt; an IOException while streaming either resource from getClass().getResourceAsStream(name) reaches line 125.

Common situations: The spring-boot-gradle-plugin jar got corrupted/partially downloaded in the Gradle cache; a custom build shades or relocates the plugin and strips the template resources; a broken filesystem or interrupted download left the jar incomplete; an unusual classloader (some fat-jar/monorepo tooling) hides plugin-internal resources.

Related errors

• Failed to set file mode on CopySpec
• Main class name has not been configured and it could not be
• Failed to read main class name from '{}'
• Failed to create {}
• Failed to add {} to {}

AI-assisted analysis of spring-projects/spring-boot@5b2dbdbb8b (2026-08-04). Data as JSON: /data/errors/7b3de5608b551d21.json. Report an issue: GitHub.