didi/DoKit · error · NullPointerException

headers == null

Error message

headers == null

What it means

Thrown by the Map overload CommonHeaders.of(Map<String, String> headers) when the passed map is null. This factory flattens the map into the internal name/value array, so a non-null map is a hard precondition.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/kit/network/common/CommonHeaders.java:189

    }

    // Check for malformed headers.
    for (int i = 0; i < namesAndValues.length; i += 2) {
      String name = namesAndValues[i];
      String value = namesAndValues[i + 1];
      if (name.length() == 0 || name.indexOf('\0') != -1 || value.indexOf('\0') != -1) {
        throw new IllegalArgumentException("Unexpected header: " + name + ": " + value);
      }
    }

    return new CommonHeaders(namesAndValues);
  }

  /**
   * Returns headers for the header names and values in the {@link Map}.
   */
  public static CommonHeaders of(Map<String, String> headers) {
    if (headers == null) throw new NullPointerException("headers == null");

    // Make a defensive copy and clean it up.
    String[] namesAndValues = new String[headers.size() * 2];
    int i = 0;
    for (Map.Entry<String, String> header : headers.entrySet()) {
      if (header.getKey() == null || header.getValue() == null) {
        throw new IllegalArgumentException("Headers cannot be null");
      }
      String name = header.getKey().trim();
      String value = header.getValue().trim();
      if (name.length() == 0 || name.indexOf('\0') != -1 || value.indexOf('\0') != -1) {
        throw new IllegalArgumentException("Unexpected header: " + name + ": " + value);
      }
      namesAndValues[i] = name;
      namesAndValues[i + 1] = value;
      i += 2;
    }

View on GitHub (pinned to 626827cddb)

Solutions

1. Default the map: of(map == null ? Collections.emptyMap() : map)
2. Use CommonHeaders.EMPTY-style empty Builder result when no headers are needed
3. Fix the config layer to always supply a non-null (possibly empty) map

Example fix

// before
CommonHeaders h = CommonHeaders.of(extraHeaders); // extraHeaders == null by default

// after
CommonHeaders h = CommonHeaders.of(extraHeaders != null ? extraHeaders : new HashMap<String, String>());

Map<String, String> safe = (headersMap == null) ? new LinkedHashMap<String, String>() : headersMap;
CommonHeaders h = CommonHeaders.of(safe);

boolean isNonNullHeaderMap(Map<String, String> m) { return m != null; }

When it happens

Trigger: Calling CommonHeaders.of((Map<String, String>) null), e.g. forwarding request.headers plus a nullable extra-headers map that was never defaulted.

Common situations: Optional request extras (extra headers map from a mock template or config) that are null by default and are forwarded without a null check.

Related errors

• namesAndValues == null
• Headers cannot be null
• name == null
• value == null
• field == null

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/9fa883b4d4df62fa. Report an issue: GitHub.