alibaba/arthas · warning · IllegalArgumentException

Line range syntax is not supported in the first version: {}

Error message

Line range syntax is not supported in the first version: {}

What it means

Thrown as IllegalArgumentException by LineCommand.parseLines when a line-spec value contains a dash ('-'), indicating a range (e.g. '10-20'). Range syntax is intentionally not implemented in this first version of the command — only discrete, comma-separated single line numbers are accepted. The offending value is echoed.

Source

Thrown at core/src/main/java/com/taobao/arthas/core/command/monitor200/LineCommand.java:288

    }

    static Set<Integer> parseLines(List<String> lineSpecs) {
        if (lineSpecs == null || lineSpecs.isEmpty()) {
            throw new IllegalArgumentException("The --line option is required unless --list-lines is used.");
        }
        Set<Integer> result = new LinkedHashSet<Integer>();
        for (String lineSpec : lineSpecs) {
            if (StringUtils.isEmpty(lineSpec)) {
                continue;
            }
            String[] parts = lineSpec.split(",");
            for (String part : parts) {
                String value = part.trim();
                if (value.length() == 0) {
                    continue;
                }
                if (value.indexOf('-') >= 0) {
                    throw new IllegalArgumentException("Line range syntax is not supported in the first version: "
                            + value);
                }
                final int lineNumber;
                try {
                    lineNumber = Integer.parseInt(value);
                } catch (NumberFormatException e) {
                    throw new IllegalArgumentException("Invalid line number: " + value);
                }
                if (lineNumber <= 0) {
                    throw new IllegalArgumentException("Line number must be greater than 0: " + value);
                }
                result.add(lineNumber);
                if (result.size() > MAX_LINE_COUNT) {
                    throw new IllegalArgumentException("Too many line numbers, maximum is " + MAX_LINE_COUNT + ".");
                }
            }
        }
        if (result.isEmpty()) {

View on GitHub (pinned to 21cf2e9ba5)

Solutions

1. Replace the range with an explicit comma-separated list of single lines (e.g. '10,11,12,...,20').
2. If you need many lines, generate the comma list programmatically.
3. Check release notes for a newer Arthas version that may have added range support.

Example fix

// before
line com.example.Foo --line 10-20

// after
line com.example.Foo --line 10,11,12,13,14,15,16,17,18,19,20

if (value.indexOf('-') >= 0) {
    // expand to a comma-separated list of single lines before passing to parseLines
}

static boolean isDiscreteLineSpec(String s) { return s != null && s.indexOf('-') < 0; }

try { Set<Integer> lines = LineCommand.parseLines(lineSpecs); } catch (IllegalArgumentException e) { // expand ranges into explicit lists }

When it happens

Trigger: Pass a --line value using range syntax such as '10-20', '5-10', or any token containing '-'. The indexOf('-') check trips before numeric parsing.

Common situations: User assumes range syntax is supported (common in other tools' breakpoint commands); copy-paste of a range from documentation of a different tool.

Related errors

• '{s}' is not a valid size. Should be numeric value followed
• '{s}' is not a valid timespan. Shoule be numeric value follo
• {optionName} must not be blank.
• {optionName} must be greater than 0.
• {optionName} is invalid: {value}

AI-assisted analysis of alibaba/arthas@21cf2e9ba5 (2026-08-14). Data as JSON: /api/errors/6f2ce07b7e3471ea. Report an issue: GitHub.