apache/cassandra · error · org.apache.cassandra.config.YAMLException

No readable property '%s' on class: %s

Error message

No readable property '%s' on class: %s

What it means

In DefaultLoader's property accessor, get() refuses to read a property whose readMethod is unavailable (isReadable() false), throwing YAMLException. This happens while mapping cassandra.yaml onto config classes when the YAML references a property that has no accessible getter on the target class.

Source

Thrown at src/java/org/apache/cassandra/config/DefaultLoader.java:104

    /**
     * .get() acts differently than .set() and doesn't do a good job showing the cause of the failure, this
     * class rewrites to make the errors easier to reason with.
     */
    private static class MethodPropertyPlus extends MethodProperty
    {
        private final Method readMethod;

        public MethodPropertyPlus(PropertyDescriptor property)
        {
            super(property);
            this.readMethod = property.getReadMethod();
        }

        @Override
        public Object get(Object object)
        {
            if (!isReadable())
                throw new YAMLException("No readable property '" + getName() + "' on class: " + object.getClass().getName());

            try
            {
                return readMethod.invoke(object);
            }
            catch (IllegalAccessException e)
            {
                throw new YAMLException("Unable to find getter for property '" + getName() + "' on class " + object.getClass().getName(), e);
            }
            catch (InvocationTargetException e)
            {
                throw new YAMLException("Failed calling getter for property '" + getName() + "' on class " + object.getClass().getName(), e.getCause());
            }
        }
    }
}

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Remove or correct the offending key in cassandra.yaml so it matches an existing config property.
2. Add a public getter for the property on the target config class (or make the existing one accessible).
3. Align the YAML with the config schema of the Cassandra version in use (check for renamed fields after upgrade).

Example fix

// before (cassandra.yaml)
old_field: 42
// after (cassandra.yaml)
# key removed or renamed to the current schema name
new_field: 42

// pre-validate yaml keys against the Config schema before loading:
// for each yaml key, assert a matching readable property exists on the target class

null

try { loader.load(yamlStream); } catch (YAMLException e) { log.error("unreadable config property: " + e.getMessage(), e); }

When it happens

Trigger: Loading a cassandra.yaml that contains a key mapping to a property object without a readable (public getter) method, e.g. a removed/renamed config field or a typo'd key mapped onto a class with no matching getter.

Common situations: Downgrading Cassandra so the YAML has fields the config class no longer exposes as readable; typos in yaml keys; custom config classes missing getters for declared fields.

Related errors

• Unable to find getter for property '%s' on class %s
• Failed to instantiate %s
• Invalid data rate: ${value} Accepted units: MiB/s, KiB/s, B/
• Invalid data rate: ${value}. It shouldn't be more than ${max
• Invalid data storage: ${value} Accepted units:${acceptedUnit

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/3ffd44b1e1af9d0c. Report an issue: GitHub.