junit-team/junit5 · error · JUnitException

Failed to initialize XML events writer

Error message

Failed to initialize XML events writer

What it means

Thrown by OpenTestReportGeneratingListener.testPlanExecutionStarted() as a JUnitException wrapping any failure from createDocumentWriter() or reportInfrastructure(). This is the top-level guard around XML events writer initialisation (socket or file mode) plus infrastructure/git reporting. The root cause is attached as the exception's cause.

Source

Thrown at junit-platform-reporting/src/main/java/org/junit/platform/reporting/open/xml/OpenTestReportGeneratingListener.java:143

	}

	@Override
	public void testPlanExecutionStarted(TestPlan testPlan) {
		ConfigurationParameters config = testPlan.getConfigurationParameters();
		if (isEnabled(config)) {
			NamespaceRegistry namespaceRegistry = NamespaceRegistry.builder(Namespace.REPORTING_CORE) //
					.add("e", Namespace.REPORTING_EVENTS) //
					.add("git", Namespace.REPORTING_GIT) //
					.add("java", Namespace.REPORTING_JAVA) //
					.add("junit", JUnitFactory.NAMESPACE, "https://schemas.junit.org/open-test-reporting/junit-1.9.xsd") //
					.build();
			outputDir = testPlan.getOutputDirectoryCreator().getRootDirectory();
			try {
				eventsFileWriter = createDocumentWriter(config, namespaceRegistry);
				reportInfrastructure(config);
			}
			catch (Exception e) {
				throw new JUnitException("Failed to initialize XML events writer", e);
			}
		}
	}

	private DocumentWriter<Events> createDocumentWriter(ConfigurationParameters config,
			NamespaceRegistry namespaceRegistry) throws Exception {
		return config.get(SOCKET_PROPERTY_NAME, Integer::valueOf) //
				.map(port -> {
					try {
						Socket socket = new Socket(InetAddress.getLoopbackAddress(), port);
						Writer writer = new OutputStreamWriter(socket.getOutputStream(), StandardCharsets.UTF_8);
						return Events.createDocumentWriter(namespaceRegistry, writer);
					}
					catch (Exception e) {
						throw new JUnitException("Failed to connect to socket on port " + port, e);
					}
				}) //
				.orElseGet(() -> {

View on GitHub (pinned to 956246301e)

Solutions

1. Inspect the wrapped cause (getCause()) to identify socket, file, or git failure and address that specifically.
2. If you do not need XML reporting, set junit.platform.reporting.open.xml.enabled=false (or leave unset).
3. Ensure the output directory is writable and the socket port (if set) is listening.
4. Align the opentest4j-reporting dependency version with the JUnit Platform version in use.

Example fix

// before
junit.platform.reporting.open.xml.enabled = true
# output dir read-only -> JUnitException on init

// after
junit.platform.reporting.open.xml.enabled = true
junit.platform.output.dir = target/test-reports  # writable

// Only enable XML reporting when prerequisites hold
boolean enabled = Boolean.getBoolean("junit.platform.reporting.open.xml.enabled");
if (enabled) {
    Path out = Path.of(System.getProperty("junit.platform.output.dir", "target"));
    Files.createDirectories(out);
    if (System.getProperty("junit.platform.reporting.open.xml.socket") != null
        && !socketListening(port)) enabled = false;
}

try {
    listener.testPlanExecutionStarted(testPlan);
} catch (JUnitException e) {
    // log getCause(); disable reporting or fix env; tests can still run without the listener
    log.warn("XML reporting init failed: {}", e.getMessage());
}

When it happens

Trigger: junit.platform.reporting.open.xml.enabled=true and either the socket connection fails, the events file cannot be created, NamespaceRegistry/DocumentWriter construction fails, or reportInfrastructure throws (e.g. git process failure). The broad catch at line 142-144 wraps all of these.

Common situations: Misconfigured socket port, unwritable output directory, git enabled but missing, or an incompatible opentest4j-reporting library version on the classpath. Enabling XML reporting in a restricted CI environment.

Related errors

• Failed to create XML events file
• Failed to close XML events file
• Failed to start process
• Failed to connect to socket on port
• Cannot override the standard style 'NONE'

AI-assisted analysis of junit-team/junit5@956246301e (2026-08-04). Data as JSON: /data/errors/158a42f566e1d60d.json. Report an issue: GitHub.