apache/cassandra · error · ConfigurationException

Invalid value for system property: expected integer value bu

Error message

Invalid value for system property: expected integer value but got '%s'

What it means

Thrown by the INTEGER_CONVERTER used by CassandraRelevantProperties int getters when the property value cannot be decoded as an integer via Integer.decode. It surfaces as a ConfigurationException identifying the offending value.

Source

Thrown at src/java/org/apache/cassandra/config/CassandraRelevantProperties.java:1111

    public interface PropertyConverter<T>
    {
        T convert(String value);
    }

    private static final PropertyConverter<String> STRING_CONVERTER = value -> value;

    private static final PropertyConverter<Boolean> BOOLEAN_CONVERTER = Boolean::parseBoolean;

    private static final PropertyConverter<Integer> INTEGER_CONVERTER = value ->
    {
        try
        {
            return Integer.decode(value);
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException(String.format("Invalid value for system property: " +
                                                           "expected integer value but got '%s'", value));
        }
    };

    private static final PropertyConverter<Long> LONG_CONVERTER = value ->
    {
        try
        {
            return Long.decode(value);
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException(String.format("Invalid value for system property: " +
                                                           "expected long value but got '%s'", value));
        }
    };

    private static final PropertyConverter<Long> SIZE_IN_BYTES_CONVERTER = value ->

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Set the property to a plain integer value (optionally 0x hex / 0 octal per Integer.decode)
Use a size-aware property/getter (getSizeInBytes) if the value should support MiB/GB suffixes
Check the value for stray whitespace or quotes in your scripts
Catch ConfigurationException at startup to fail fast with a clear message

Example fix

// before
-Dcassandra.num_tokens=16,2
// after
-Dcassandra.num_tokens=16

Defensive patterns

Strategy: validation

Validate before calling

String v = System.getProperty("cassandra.some_int");
if (v != null) {
    try { Integer.decode(v.trim()); }
    catch (NumberFormatException e) { throw new IllegalArgumentException("Not an int: " + v); }
}

Try / catch

try {
    int v = CassandraRelevantProperties.SOME_INT.getInt();
} catch (ConfigurationException e) {
    int v = 16; // fallback
}

Prevention

Use plain integer literals for int properties
Use size-aware getters for MiB/GB suffixed values
Trim and unquote values generated by templating tools

When it happens

Trigger: Setting a system property read as an int to a non-integer string, e.g. -Dcassandra.some_int=1024MiB or 'abc', or a value outside int range.

Common situations: Copy-pasting size-style values into integer properties, quoting errors in cassandra-env.sh leaving stray characters, unit conversions confusion between raw ints and size strings.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/40842c3538be0c3e. Report an issue: GitHub.