What causes "Failed to parse delimiter: `Hex str is empty`" in apache/seatunnel?

Provide the full hex encoding of the delimiter, e.g. "\\x09" for tab or "\\x2C" for comma

apache/seatunnel · error · StarRocksConnectorException

ILLEGAL_ARGUMENT

ILLEGAL_ARGUMENT

Error message

Failed to parse delimiter: `Hex str is empty`

What it means

StarRocksDelimiterParser.parse handles delimiters given in hex form like '\x09'. When the value starts with \x (case-insensitive), the remainder after '\X' is treated as hex; if that remainder is empty (the delimiter is literally '\x' or '\X'), an ILLEGAL_ARGUMENT StarRocksConnectorException is thrown because an empty hex string encodes no separator.

Solutions

Provide the full hex encoding of the delimiter, e.g. "\\x09" for tab or "\\x2C" for comma
Use the literal character instead (e.g. delimiter = "\t") if hex encoding isn't needed
Validate the delimiter config before submitting the job

Example fix

// before
 delimiter = "\\x"
// after
 delimiter = "\\x09" // or a literal "\t"

Defensive patterns

Strategy: validation

Validate before calling

String d = config.getString("delimiter"); if (d != null && d.toUpperCase().startsWith("\\X") && d.length() <= 2) throw new IllegalArgumentException("hex delimiter needs digits after \\x, e.g. \\x09");

Type guard

boolean isCompleteHexDelimiter(String s) { return !(s.toUpperCase().startsWith("\\X")) || s.length() > 2; }

Try / catch

try { submitJob(cfg); } catch (StarRocksConnectorException e) { if (e.getErrorCode() == CommonErrorCodeDeprecated.ILLEGAL_ARGUMENT && e.getMessage().contains("Failed to parse delimiter")) { /* fix delimiter value in config */ } throw e; }

Prevention

Always write hex delimiters with at least two hex digits (\\x09, \\x01)
Prefer literal characters for printable delimiters
Validate delimiter values in your config pipeline before submission

When it happens

Trigger: Configuring a delimiter option as "\\x" or "\\X" with no hex digits following — e.g. delimiter = "\\x" in the HOCON file.

Common situations: Copy-paste errors truncating '\\x09' to '\\x'; misunderstanding the hex-delimiter feature and thinking \\x alone means 'hex mode'.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/148dce16e415bf31. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-connectors-v2/connector-starrocks/src/main/java/org/apache/seatunnel/connectors/seatunnel/starrocks/serialize/StarRocksDelimiterParser.java:42

import java.io.StringWriter;

public class StarRocksDelimiterParser {
    private static final int SHIFT = 4;

    private static final String HEX_STRING = "0123456789ABCDEF";

    public static String parse(String sp, String dSp) throws RuntimeException {
        if (Strings.isNullOrEmpty(sp)) {
            return dSp;
        }
        if (!sp.toUpperCase().startsWith("\\X")) {
            return sp;
        }
        String hexStr = sp.substring(2);
        // check hex str
        if (hexStr.isEmpty()) {
            throw new StarRocksConnectorException(
                    CommonErrorCodeDeprecated.ILLEGAL_ARGUMENT,
                    "Failed to parse delimiter: `Hex str is empty`");
        }
        if (hexStr.length() % 2 != 0) {
            throw new StarRocksConnectorException(
                    CommonErrorCodeDeprecated.ILLEGAL_ARGUMENT,
                    "Failed to parse delimiter: `Hex str is empty`");
        }
        for (char hexChar : hexStr.toUpperCase().toCharArray()) {
            if (HEX_STRING.indexOf(hexChar) == -1) {
                throw new StarRocksConnectorException(
                        CommonErrorCodeDeprecated.ILLEGAL_ARGUMENT,
                        "Failed to parse delimiter: `Hex str is empty`");
            }
        }
        // transform to separator
        StringWriter writer = new StringWriter();
        for (byte b : hexStrToBytes(hexStr)) {

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