openzipkin/zipkin · error · NullPointerException

value == null

Error message

value == null

What it means

Annotation.create throws NullPointerException when value is null. An Annotation is a (timestamp, value) pair where value names the event (e.g. 'sr', 'cache.miss'); a null value has no meaning, so creation is rejected eagerly instead of failing later during encoding or comparison.

Source

Thrown at zipkin/src/main/java/zipkin2/Annotation.java:21

 * SPDX-License-Identifier: Apache-2.0
 */
package zipkin2;

import java.io.ObjectStreamException;
import java.io.Serializable;
import java.io.StreamCorruptedException;

/**
 * Associates an event that explains latency with a timestamp.
 *
 * <p>Unlike log statements, annotations are often codes: Ex. {@code cache.miss}.
 */
//@Immutable
public final class Annotation implements Comparable<Annotation>, Serializable { // for Spark jobs
  private static final long serialVersionUID = 0L;

  public static Annotation create(long timestamp, String value) {
    if (value == null) throw new NullPointerException("value == null");
    return new Annotation(timestamp, value);
  }

  /**
   * Microseconds from epoch.
   *
   * <p>This value should be set directly by instrumentation, using the most precise value possible.
   * For example, {@code gettimeofday} or multiplying {@link System#currentTimeMillis} by 1000.
   */
  public long timestamp() {
    return timestamp;
  }

  /**
   * Usually a short tag indicating an event, like {@code cache.miss} or {@code error}
   */
  public String value() {
    return value;

View on GitHub (pinned to 878ce2a1fa)

Solutions

1. Skip annotations whose value is null instead of creating them.
2. Default or validate the value upstream: requireNonNull(value, 'annotation value required').
3. If parsing external data, treat a missing value as a data error and log/drop the record.

Example fix

// before
Annotation a = Annotation.create(ts, map.get("event")); // null when key absent

// after
String value = map.get("event");
if (value != null) annotations.add(Annotation.create(ts, value));

String value = rawValue;
if (value != null) annotations.add(Annotation.create(timestamp, value));

When it happens

Trigger: Calling Annotation.create(timestamp, null), often with a value pulled from a map or parsed from input that was absent.

Common situations: Converting wire/JSON data where the annotation value field is missing; instrumentation code building annotations from dynamic key/value pairs where the value expression evaluates to null.

Related errors

• parent == null
• child == null
• Incomplete annotation at {}
• Missing :
• invalid port

AI-assisted analysis of openzipkin/zipkin@878ce2a1fa (2026-08-14). Data as JSON: /api/errors/fa974a6b548d2ac7. Report an issue: GitHub.