alibaba/nacos · critical · IllegalArgumentException

invalid PER_TASK_CONFIG_SIZE, expected value type double

Error message

invalid PER_TASK_CONFIG_SIZE, expected value type double

What it means

Thrown by ParamUtil.initPerTaskConfigSize() during static class initialization when the PER_TASK_CONFIG_SIZE property cannot be parsed as a double via Double.parseDouble. The default value is "3000". Like other ParamUtil static init errors, this surfaces as ExceptionInInitializerError and blocks the entire Nacos client from loading.

Solutions

Locate the offending PER_TASK_CONFIG_SIZE value from the exception message embedded in the ExceptionInInitializerError.
Check JVM system properties, environment variables, and nacos-client.properties for PER_TASK_CONFIG_SIZE.
Change the value to a valid decimal number (e.g. 3000 or 3000.0).
Ensure no locale-dependent comma separators are used; use a period as the decimal point.

Example fix

// before
System.setProperty("PER_TASK_CONFIG_SIZE", "3,000");

// after
System.setProperty("PER_TASK_CONFIG_SIZE", "3000");

Defensive patterns

Strategy: validation

Validate before calling

String rawSize = System.getProperty("PER_TASK_CONFIG_SIZE", "3000");
try {
    Double.parseDouble(rawSize);
} catch (NumberFormatException e) {
    throw new IllegalStateException("PER_TASK_CONFIG_SIZE must be a double, got: " + rawSize, e);
}

Prevention

Validate PER_TASK_CONFIG_SIZE at startup before the Nacos client class-loads ParamUtil.
Ensure locale-independent decimal formatting (use period, not comma).
Centralize Nacos property configuration in one validated configuration class.

When it happens

Trigger: Setting -DPER_TASK_CONFIG_SIZE to a non-numeric string (e.g. "large", "3.0.0", "3,000"). This property controls the max config payload size processed per single task in the config client.

Common situations: Operators mis-type the property name or value in JVM args or environment variables; locale issues where a comma is used as the decimal separator; values copied from documentation that include units or labels.

Related errors

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/5ab64a28f0cff557. Report an issue: GitHub.

Appendix: source

Thrown at client/src/main/java/com/alibaba/nacos/client/utils/ParamUtil.java:96

        try {
            tmp = NacosClientProperties.PROTOTYPE.getProperty(NACOS_READ_TIMEOUT_KEY,
                DEFAULT_NACOS_READ_TIMEOUT);
            return Integer.parseInt(tmp);
        } catch (NumberFormatException e) {
            final String msg = "[http-client] invalid read timeout:" + tmp;
            LOGGER.error("[settings] " + msg, e);
            throw new IllegalArgumentException(msg, e);
        }
    }
    
    private static double initPerTaskConfigSize() {
        try {
            return Double.parseDouble(
                NacosClientProperties.PROTOTYPE.getProperty(PER_TASK_CONFIG_SIZE_KEY,
                    DEFAULT_PER_TASK_CONFIG_SIZE_KEY));
        } catch (NumberFormatException e) {
            LOGGER.error("[PER_TASK_CONFIG_SIZE] PER_TASK_CONFIG_SIZE invalid", e);
            throw new IllegalArgumentException(
                "invalid PER_TASK_CONFIG_SIZE, expected value type double", e);
        }
    }
    
    public static int getConnectTimeout() {
        return connectTimeout;
    }
    
    public static void setConnectTimeout(int connectTimeout) {
        ParamUtil.connectTimeout = connectTimeout;
    }
    
    public static int getReadTimeout() {
        return readTimeout;
    }
    
    public static void setReadTimeout(int readTimeout) {
        ParamUtil.readTimeout = readTimeout;

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