apache/flink · error · IllegalArgumentException

The jarFile and entryPointClassName can not be null at the s

Error message

The jarFile and entryPointClassName can not be null at the same time.

What it means

Thrown by PackagedProgram.Builder.build() when both jarFile and entryPointClassName are null. The builder requires at least one of these to construct a program — a jar to infer the main class from, or an explicit entry point class name.

Source

Thrown at flink-clients/src/main/java/org/apache/flink/client/program/PackagedProgram.java:697

        public Builder setConfiguration(Configuration configuration) {
            this.configuration = configuration;
            return this;
        }

        public Builder setSavepointRestoreSettings(
                SavepointRestoreSettings savepointRestoreSettings) {
            this.savepointRestoreSettings = savepointRestoreSettings;
            return this;
        }

        @VisibleForTesting
        public List<URL> getUserClassPaths() {
            return userClassPaths;
        }

        public PackagedProgram build() throws ProgramInvocationException {
            if (jarFile == null && entryPointClassName == null) {
                throw new IllegalArgumentException(
                        "The jarFile and entryPointClassName can not be null at the same time.");
            }
            return new PackagedProgram(
                    jarFile,
                    userClassPaths,
                    entryPointClassName,
                    configuration,
                    savepointRestoreSettings,
                    args);
        }

        private Builder() {}
    }

    public static Builder newBuilder() {
        return new Builder();
    }
}

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Provide a jar file via setJarFile(URI) or setJarFile(File).
2. Or provide an entry point class name via setEntryPointClassName(String).
3. Review builder call chain to ensure at least one is set before build().

Example fix

// before
PackagedProgram.newBuilder()
    .setConfiguration(conf)
    .build();  // both jarFile and entryPointClassName are null

// after
PackagedProgram.newBuilder()
    .setJarFile(jarFile)
    .setConfiguration(conf)
    .build();

if (jarFile == null && entryPointClassName == null) {
    throw new IllegalArgumentException(
        "Must provide either a jar file or an entry point class name.");
}
PackagedProgram.newBuilder()
    .setJarFile(jarFile)
    .setEntryPointClassName(entryPointClassName)
    .build();

try {
    PackagedProgram.newBuilder().build();
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("can not be null at the same time")) {
        // set jarFile or entryPointClassName before build
    }
    throw e;
}

When it happens

Trigger: Calling PackagedProgram.newBuilder().build() without calling setJarFile or setEntryPointClassName (or calling only configuration/savepoint setters). This is an IllegalArgumentException indicating a contract violation.

Common situations: Programmatic builder usage where conditional logic skipped both setters, or a copy-paste error that removed the setJarFile call.

Related errors

• {e.getMessage()}
• Cannot access jar file{t.getMessage() == null ? "." : ": " +
• At least one trigger condition must be configured.
• The cpu cores should be positive.
• The cpu cores and task heap memory are required when specify

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/f4fc9d52661e87db. Report an issue: GitHub.