google/gson · error · JsonSyntaxException

Failed parsing '" + s + "' as SQL Time; at path " + in.getPr

Error message

Failed parsing '" + s + "' as SQL Time; at path " + in.getPreviousPath()

What it means

SqlTimeTypeAdapter parses the JSON string with SimpleDateFormat("hh:mm:ss a") (12-hour clock with AM/PM marker, e.g. '01:30:00 PM'). A ParseException is wrapped as JsonSyntaxException. The format is locale-sensitive and synchronized.

Source

Thrown at gson/src/main/java/com/google/gson/internal/sql/SqlTimeTypeAdapter.java:70

  private final DateFormat format = new SimpleDateFormat("hh:mm:ss a");

  private SqlTimeTypeAdapter() {}

  @Override
  public Time read(JsonReader in) throws IOException {
    if (in.peek() == JsonToken.NULL) {
      in.nextNull();
      return null;
    }
    String s = in.nextString();
    synchronized (this) {
      TimeZone originalTimeZone = format.getTimeZone(); // Save the original time zone
      try {
        Date date = format.parse(s);
        return new Time(date.getTime());
      } catch (ParseException e) {
        throw new JsonSyntaxException(
            "Failed parsing '" + s + "' as SQL Time; at path " + in.getPreviousPath(), e);
      } finally {
        format.setTimeZone(originalTimeZone); // Restore the original time zone
      }
    }
  }

  @Override
  public void write(JsonWriter out, Time value) throws IOException {
    if (value == null) {
      out.nullValue();
      return;
    }
    String timeString;
    synchronized (this) {
      timeString = format.format(value);
    }
    out.value(timeString);

View on GitHub (pinned to 8b8628c656)

Solutions

Provide the time string in 'hh:mm:ss a' form (e.g. '02:30:00 PM').
Register a custom TypeAdapter<java.sql.Time> using a 24-hour format like 'HH:mm:ss'.
Deserialize as java.time.LocalTime and convert if the SQL type is not essential.

Example fix

// before
java.sql.Time t = gson.fromJson("\"14:30:00\"", java.sql.Time.class);

// after
Gson gson = new GsonBuilder().registerTypeAdapter(java.sql.Time.class, new TypeAdapter<java.sql.Time>() {
    @Override public java.sql.Time read(JsonReader in) throws IOException { return java.sql.Time.valueOf(in.nextString()); }
    @Override public void write(JsonWriter out, java.sql.Time v) throws IOException { out.value(v.toString()); }
}).create();

Defensive patterns

Strategy: validation

Validate before calling

boolean isSqlTimeParsable(String s) {
  if (s == null) return false;
  try { java.text.DateFormat f = new java.text.SimpleDateFormat("hh:mm:ss a", Locale.ENGLISH); f.parse(s); return true; }
  catch (java.text.ParseException e) { return false; }
}

Type guard

static boolean matchesDefaultSqlTimeFormat(String s) {
  return s != null && s.matches("\\d{2}:\\d{2}:\\d{2} (AM|PM)");
}

Try / catch

try {
  java.sql.Time t = gson.fromJson(json, java.sql.Time.class);
} catch (JsonSyntaxException e) {
  // register a 24-hour HH:mm:ss adapter and retry
}

Prevention

Register a java.sql.Time adapter with the producer's 24-hour format.
Pin Locale.ENGLISH for AM/PM symbols if you keep the default format.
Prefer java.time.LocalTime for new code.

When it happens

Trigger: Deserializing a JSON value into a java.sql.Time field where the string is not in 'hh:mm:ss a' 12-hour form (e.g. '14:30:00' 24-hour, ISO format, or missing AM/PM).

Common situations: Producer emits 24-hour ISO times, missing AM/PM marker, or a locale whose DateTimeSymbols lack the expected symbols; mismatched conventions across system layers.

Related errors

AI-assisted analysis of google/gson@8b8628c656 (2026-08-04). Data as JSON: /data/errors/81be8f7cafd7491b.json. Report an issue: GitHub.