apache/flink · error · ProgramInvocationException

Neither a '{MANIFEST_ATTRIBUTE_MAIN_CLASS}', nor a '{MANIFES

Error message

Neither a '{MANIFEST_ATTRIBUTE_MAIN_CLASS}', nor a '{MANIFEST_ATTRIBUTE_ASSEMBLER_CLASS}' entry was found in the jar file.

What it means

Thrown by getEntryPointClassNameFromJar when the manifest is present but contains neither Flink's 'program-class' attribute nor the standard Java 'Main-Class' attribute. The manifest exists but does not declare an entry point, so Flink cannot determine the driver class.

Source

Thrown at flink-clients/src/main/java/org/apache/flink/client/program/PackagedProgram.java:441

                        "No manifest found in jar file '"
                                + jarFile.getPath()
                                + "'. The manifest is need to point to the program's main class.");
            }

            Attributes attributes = manifest.getMainAttributes();

            // check for a "program-class" entry first
            className = attributes.getValue(PackagedProgram.MANIFEST_ATTRIBUTE_ASSEMBLER_CLASS);
            if (className != null) {
                return className;
            }

            // check for a main class
            className = attributes.getValue(PackagedProgram.MANIFEST_ATTRIBUTE_MAIN_CLASS);
            if (className != null) {
                return className;
            } else {
                throw new ProgramInvocationException(
                        "Neither a '"
                                + MANIFEST_ATTRIBUTE_MAIN_CLASS
                                + "', nor a '"
                                + MANIFEST_ATTRIBUTE_ASSEMBLER_CLASS
                                + "' entry was found in the jar file.");
            }
        } finally {
            try {
                jar.close();
            } catch (Throwable t) {
                throw new ProgramInvocationException(
                        "Could not close the JAR file: " + t.getMessage(), t);
            }
        }
    }

    @Nullable
    private static URL loadJarFile(File jar) throws ProgramInvocationException {

View on GitHub (pinned to 2f3c205e92)

Solutions

Specify the entry class explicitly with --class <fully.qualified.MainClass>.
Rebuild the jar adding 'Main-Class' to the manifest (Maven shade/jar plugin 'mainClass'), or Flink's 'program-class' attribute.
Verify the manifest attribute name matches exactly 'Main-Class' or 'program-class' (case-sensitive).

Example fix

# before: jar manifest has neither Main-Class nor program-class
flink run /opt/jobs/myjob.jar

# after (runtime): pass the class
flink run -c com.example.MyJob /opt/jobs/myjob.jar

# after (build, pom.xml)
# <plugin><artifactId>maven-shade-plugin</artifactId>
#   <configuration><transformers>
#     <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
#       <mainClass>com.example.MyJob</mainClass>
#     </transformer>
#   </transformers></configuration></plugin>

Defensive patterns

Strategy: validation

Validate before calling

try (JarFile jf = new JarFile(jarFile)) {
    Manifest m = jf.getManifest();
    if (m == null
        || (m.getMainAttributes().getValue("Main-Class") == null
            && m.getMainAttributes().getValue("program-class") == null)) {
        // jar cannot self-describe its entry point — caller must pass --class
        throw new IllegalArgumentException("Jar has no Main-Class/program-class attribute");
    }
}

Try / catch

try {
    PackagedProgram.newBuilder().setJarFile(jarFile).build();
} catch (ProgramInvocationException pie) {
    if (pie.getMessage().contains("Neither a")) {
        // rebuild with Main-Class, or pass .setEntryPointClassName()
    }
    throw pie;
}

Prevention

Set 'Main-Class' (or Flink 'program-class') in the manifest at build time.
Pass --class explicitly for jars without a self-describing manifest.
Check attribute names are exactly 'Main-Class' / 'program-class' (case-sensitive).

When it happens

Trigger: The jar's META-INF/MANIFEST.MF exists but has no 'program-class' and no 'Main-Class' header. Checked in order: program-class first, then Main-Class.

Common situations: A library jar that has a manifest (e.g. for vendor metadata) but was never configured as an executable jar; a manifest whose main-class was set under a different/custom attribute name.

Related errors

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/76096a76da401000. Report an issue: GitHub.