didi/DoKit · error · NullPointerException

namesAndValues == null

Error message

namesAndValues == null

What it means

Thrown by CommonHeaders.of(String... namesAndValues) when the varargs array is null. DoKit's CommonHeaders is a lightweight okhttp-Headers-style container used to snapshot request/response headers for the network inspector; the factory requires a non-null alternating name/value array.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/kit/network/common/CommonHeaders.java:161

    }
    return result;
  }

  private static String get(String[] namesAndValues, String name) {
    for (int i = namesAndValues.length - 2; i >= 0; i -= 2) {
      if (name.equalsIgnoreCase(namesAndValues[i])) {
        return namesAndValues[i + 1];
      }
    }
    return null;
  }

  /**
   * Returns headers for the alternating header names and values. There must be an even number of
   * arguments, and they must alternate between header names and values.
   */
  public static CommonHeaders of(String... namesAndValues) {
    if (namesAndValues == null) throw new NullPointerException("namesAndValues == null");
    if (namesAndValues.length % 2 != 0) {
      throw new IllegalArgumentException("Expected alternating header names and values");
    }

    // Make a defensive copy and clean it up.
    namesAndValues = namesAndValues.clone();
    for (int i = 0; i < namesAndValues.length; i++) {
      if (namesAndValues[i] == null) throw new IllegalArgumentException("Headers cannot be null");
      namesAndValues[i] = namesAndValues[i].trim();
    }

    // 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);
      }

View on GitHub (pinned to 626827cddb)

Solutions

1. Initialize the array before the call: CommonHeaders.of(new String[0]) for empty headers
2. Fix the upstream code that produced the null array (usually an uninitialized or cleared header collection)
3. Use the Builder API instead, which tolerates incremental construction

Example fix

// before
CommonHeaders h = CommonHeaders.of(headerArray); // headerArray == null

// after
CommonHeaders h = headerArray == null
    ? new CommonHeaders.Builder().build()
    : CommonHeaders.of(headerArray);

String[] safe = (headerArray == null) ? new String[0] : headerArray;
CommonHeaders h = CommonHeaders.of(safe);

boolean isNonNullHeaderArray(String[] a) { return a != null; }

When it happens

Trigger: Calling CommonHeaders.of((String[]) null) directly, or passing a null array variable such as a header array that was never initialized by an interceptor.

Common situations: Custom interceptors or mock servers forwarding a headers array that a previous stage failed to populate (e.g. a null responseHeaders array when building a mock network record).

Related errors

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

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/3a8cbc66c17aed90. Report an issue: GitHub.