flowable/flowable-engine · error · FlowableIllegalArgumentException

sessionJndi cannot be null

Error message

sessionJndi cannot be null

What it means

The MailJndiServerConfiguration.of factory creates a mail server configuration backed by a JNDI mail Session. It validates its single argument and throws FlowableIllegalArgumentException when the JNDI name is null, since a JNDI-based configuration without a lookup name is meaningless.

Solutions

1. Pass a valid, non-null JNDI name, e.g. MailJndiServerConfiguration.of("java:comp/env/mail/Session").
2. Fix the configuration source so the JNDI name is actually populated before constructing the mail client.
3. If no JNDI session exists, use a host/port-based MailServerConfiguration instead of the JNDI variant.

Example fix

// before
MailJndiServerConfiguration cfg = MailJndiServerConfiguration.of(properties.getProperty("mail.jndi")); // null

// after
String jndi = properties.getProperty("mail.jndi", "java:comp/env/mail/Session");
MailJndiServerConfiguration cfg = MailJndiServerConfiguration.of(jndi);

if (sessionJndi == null || sessionJndi.isBlank()) { throw new IllegalArgumentException("JNDI mail session name must be provided"); }

try { cfg = MailJndiServerConfiguration.of(jndiName); } catch (FlowableIllegalArgumentException e) { cfg = MailServerConfiguration.of(host, port, user, pass); }

When it happens

Trigger: Calling MailJndiServerConfiguration.of(null) — e.g. when the JNDI session name is read from a property/env var that is absent and passed straight into the factory.

Common situations: Spring/EE deployments where the mail session JNDI name is externalized to configuration and the key is missing; refactoring from hostname-based to JNDI-based mail config where the lookup name was never supplied.

Related errors

• Could not send email: Incorrect JNDI configuration
• sessionJndi has to be set for
• activatedBefore is null
• activity tenant id is null
• activity tenant id is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/3846047244c6284d. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-mail/src/main/java/org/flowable/mail/common/impl/MailJndiServerConfiguration.java:26

 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.flowable.mail.common.impl;

import org.flowable.common.engine.api.FlowableIllegalArgumentException;

/**
 * @author Filip Hrisafov
 */
public non-sealed interface MailJndiServerConfiguration extends MailServerConfiguration {

    String getSessionJndi();

    static MailJndiServerConfiguration of(String sessionJndi) {
        if (sessionJndi == null) {
            throw new FlowableIllegalArgumentException("sessionJndi cannot be null");
        }
        return () -> sessionJndi;
    }

}

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