apache/flink · error · IllegalArgumentException

Field ID must not be null.

Error message

Field ID must not be null.

What it means

Error "Field ID must not be null." thrown in apache/flink.

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/common/operators/util/FieldSet.java:51

    public static final FieldSet EMPTY_SET = new FieldSet();

    protected final Collection<Integer> collection;

    // --------------------------------------------------------------------------------------------

    /** Creates a new empty set of fields. */
    public FieldSet() {
        this.collection = Collections.emptySet();
    }

    /**
     * Creates a set with one field.
     *
     * @param fieldID The id of the field.
     */
    public FieldSet(Integer fieldID) {
        if (fieldID == null) {
            throw new IllegalArgumentException("Field ID must not be null.");
        }

        this.collection = Collections.singleton(fieldID);
    }

    /**
     * Creates a set with the given fields.
     *
     * @param fieldIDs The IDs of the fields.
     */
    public FieldSet(int... fieldIDs) {
        if (fieldIDs == null || fieldIDs.length == 0) {
            this.collection = Collections.emptySet();
        } else {
            HashSet<Integer> set = new HashSet<Integer>(2 * fieldIDs.length);
            for (int i = 0; i < fieldIDs.length; i++) {
                set.add(fieldIDs[i]);
            }

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Address the cause reported by the error message: Field ID must not be null.
2. Verify the inputs, configuration values, and classpath/dependency setup related to this operation, then retry.

Example fix

Correct the condition described ("Field ID must not be null.") and rerun the job or command.

When it happens

Trigger: Triggered at runtime when the operation fails because: Field ID must not be null.

Common situations: Commonly caused by misconfiguration, missing dependencies or files, unsupported types or operations, or invalid user input leading to: Field ID must not be null.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/da29f817b1e7b6f5. Report an issue: GitHub.