flowable/flowable-engine · error · PropertyNotWritableException

Resolver is read only!

Error message

Resolver is read only!

What it means

RootPropertyResolver can be constructed in read-only mode; any attempt to write a property through it then throws PropertyNotWritableException('Resolver is read only!'). This protects root context objects (e.g. process variables views) from mutation via EL.

Solutions

1. Construct the RootPropertyResolver with readOnly=false (new RootPropertyResolver(map, false)) if writes are intended.
2. Write values through the engine API (setVariable) instead of EL assignment.
3. Check resolver.isReadOnly() / ValueExpression.isReadOnly() before attempting setValue.

Example fix

// before
RootPropertyResolver resolver = new RootPropertyResolver(map); // readOnly default true
resolver.setValue(ctx, root, "count", 3); // throws
// after
RootPropertyResolver resolver = new RootPropertyResolver(map, false);

if (resolver.isReadOnly()) { throw new IllegalStateException("Root resolver is read-only; use engine APIs to persist values"); }

try { resolver.setValue(ctx, base, prop, value); } catch (PropertyNotWritableException e) { log.error("Resolver is read-only: {}", e.getMessage()); }

When it happens

Trigger: Calling ELResolver.setValue / ValueExpression.setValue where the resolved base is a root object handled by a read-only RootPropertyResolver (created with readOnly=true).

Common situations: Assigning to root properties in expressions evaluated with a read-only resolver; scripts that try to persist values by writing back to the root context instead of using engine APIs.

Understand the failure class

Background: Permission denied / not authorized / 403 Forbidden: access-control rejections when the caller lacks the required role, grant, or ownership — this error's family across 18 libraries.

Related errors

• Cannot find property
• Cannot invoke method
• Cannot set value of '', it's readonly!
• error.value.set.rvalue
• error.value.set.rvalue

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/163447405cfcb1a4. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/de/odysseus/el/util/RootPropertyResolver.java:96

			if (!isProperty((String) property)) {
				throw new PropertyNotFoundException("Cannot find property " + property);
			}
			return getProperty((String) property);
		}
		return null;
	}

	@Override
	public boolean isReadOnly(ELContext context, Object base, Object property) {
		return resolve(context, base, property) ? readOnly : false;
	}

	@Override
	public void setValue(ELContext context, Object base, Object property, Object value)
			throws PropertyNotWritableException {
		if (resolve(context, base, property)) {
			if (readOnly) {
				throw new PropertyNotWritableException("Resolver is read only!");
			}
			setProperty((String) property, value);
		}
	}

	@Override
	public Object invoke(ELContext context, Object base, Object method, Class<?>[] paramTypes, Object[] params) {
		if (resolve(context, base, method)) {
			throw new NullPointerException("Cannot invoke method " + method + " on null");
		}
		return null;
	}

	/**
	 * Get property value
	 * 
	 * @param property
	 *            property name

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