didi/DoKit · error · NullPointerException

value == null

Error message

value == null

What it means

Thrown by CommonHeaders.Builder.checkNameAndValue when a header value is null. The name has already been validated by this point, so the message specifically pins the missing value.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/kit/network/common/CommonHeaders.java:288

     */
    public Builder set(String name, String value) {
      checkNameAndValue(name, value);
      removeAll(name);
      addLenient(name, value);
      return this;
    }

    private void checkNameAndValue(String name, String value) {
      if (name == null) throw new NullPointerException("name == null");
      if (name.isEmpty()) throw new IllegalArgumentException("name is empty");
      for (int i = 0, length = name.length(); i < length; i++) {
        char c = name.charAt(i);
        if (c <= '\u0020' || c >= '\u007f') {
          throw new IllegalArgumentException(format(
              "Unexpected char %#04x at %d in header name: %s", (int) c, i, name));
        }
      }
      if (value == null) throw new NullPointerException("value == null");
      for (int i = 0, length = value.length(); i < length; i++) {
        char c = value.charAt(i);
        if ((c <= '\u001f' && c != '\t') || c >= '\u007f') {
          throw new IllegalArgumentException(format(
              "Unexpected char %#04x at %d in %s value: %s", (int) c, i, name, value));
        }
      }
    }

    /** Equivalent to {@code build().get(name)}, but potentially faster. */
    public String get(String name) {
      for (int i = namesAndValues.size() - 2; i >= 0; i -= 2) {
        if (name.equalsIgnoreCase(namesAndValues.get(i))) {
          return namesAndValues.get(i + 1);
        }
      }
      return null;
    }

View on GitHub (pinned to 626827cddb)

Solutions

1. Skip the header entirely when the value is absent instead of adding null
2. Default to empty string if the header must be present: builder.add(name, value == null ? "" : value)
3. Ensure login-state is resolved before headers are assembled in the interceptor chain

Example fix

// before
builder.add("Authorization", token); // token == null pre-login

// after
if (token != null) builder.add("Authorization", token);

if (value != null) builder.add(name, value); // else omit the header

boolean isNonNullHeaderValue(String v) { return v != null; }

When it happens

Trigger: Calling builder.add("Authorization", null) or set(name, null) — typically a token/cookie that has not been fetched yet when the interceptor builds the header snapshot.

Common situations: Auth tokens not yet available (pre-login requests); optional session values read from storage that return null; deserialized mock template headers with absent values.

Related errors

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

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/9b4e824554598948. Report an issue: GitHub.