flowable/flowable-engine · error · FlowableIllegalArgumentException

batchType is null

Error message

batchType is null

What it means

BatchPartQueryImpl.batchType(String) filters batch parts by the type of their parent batch. A null argument throws FlowableIllegalArgumentException immediately — the library refuses null filters. Thrown at the batchType(...) call before query execution.

Source

Thrown at modules/flowable-batch-service/src/main/java/org/flowable/batch/service/impl/BatchPartQueryImpl.java:112

            throw new FlowableIllegalArgumentException("searchKey is null");
        }
        this.searchKey = searchKey;
        return this;
    }

    @Override
    public BatchPartQuery searchKey2(String searchKey2) {
        if (searchKey2 == null) {
            throw new FlowableIllegalArgumentException("searchKey2 is null");
        }
        this.searchKey2 = searchKey2;
        return this;
    }

    @Override
    public BatchPartQuery batchType(String batchType) {
        if (batchType == null) {
            throw new FlowableIllegalArgumentException("batchType is null");
        }
        this.batchType = batchType;
        return this;
    }

    @Override
    public BatchPartQuery batchSearchKey(String searchKey) {
        if (searchKey == null) {
            throw new FlowableIllegalArgumentException("batchSearchKey is null");
        }
        this.batchSearchKey = searchKey;
        return this;
    }

    @Override
    public BatchPartQuery batchSearchKey2(String searchKey2) {
        if (searchKey2 == null) {
            throw new FlowableIllegalArgumentException("batchSearchKey2 is null");

View on GitHub (pinned to d6d39ce1c6)

Solutions

  1. Null-check the batch type before calling batchType(...).
  2. Apply the filter conditionally when the type is optional.
  3. Verify the configuration/enum providing the batch type yields a non-null value.

Example fix

// before
BatchPartQuery q = batchService.createBatchPartQuery().batchType(batchType);
// after
BatchPartQuery q = batchService.createBatchPartQuery();
if (batchType != null) {
    q.batchType(batchType);
}
Defensive patterns

Strategy: validation

Validate before calling

BatchPartQuery query = batchService.createBatchPartQuery();
if (batchType != null) {
    query.batchType(batchType);
}
List<BatchPart> parts = query.list();

Type guard

boolean hasBatchType(String t) {
    return t != null && !t.isEmpty();
}

Try / catch

try {
    List<BatchPart> parts = query.batchType(batchType).list();
} catch (org.flowable.common.engine.api.FlowableIllegalArgumentException e) {
    throw new IllegalArgumentException("batchType must not be null when filtering batch parts", e);
}

Prevention

When it happens

Trigger: Calling BatchPartQuery.batchType(null), usually when the batch type is read from configuration, a BatchType-derived string, or a nullable request parameter.

Common situations: Missing config entry for the batch type; enum-to-string conversion returning null; clients omitting the batch type parameter.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/5fee485b5f9d4934. Report an issue: GitHub.