java-native-access/jna · error · com.sun.jna.platform.win32.COM.COMException

Error occured in unadvise when trying to disconnect the…

Error message

Error occured in unadvise when trying to disconnect the listener from <this>

What it means

Generic wrapper COMException thrown by ProxyObject.unadvise() when disconnecting the listener throws a non-COMException RuntimeException. The original exception is preserved as the cause; the message includes the proxy's toString. Failures here typically mean the connection point or cookie is no longer valid.

Solutions

  1. Check getCause() for the underlying error
  2. Ensure the cookie comes from the matching advise() on the same interface/proxy
  3. Call unadvise exactly once per successful advise
  4. Unadvise before releasing the proxy, on the same thread/apartment

Example fix

// before
proxy.unadvise(MyEvents.class, cookieFromOtherProxy); // fails
// after
IComEventCallbackCookie cookie = proxy.advise(MyEvents.class, listener);
try { /* use */ } finally { proxy.unadvise(MyEvents.class, cookie); }
Defensive patterns

Strategy: try-catch

Validate before calling

if (cookie == null || iface == null) throw new IllegalArgumentException("cookie and interface required");

Type guard

boolean validPair = cookie != null && iface.isAnnotationPresent(ComInterface.class);

Try / catch

try { proxy.unadvise(iface, cookie); } catch (COMException e) { LOG.error("unadvise failed on " + this, e.getCause()); }

Prevention

When it happens

Trigger: unadvise() fails while fetching the connection point or calling IConnectionPoint.Unadvise(cookie) — e.g. an invalid/stale cookie, or the COM object already released its connection points.

Common situations: Calling unadvise with a cookie from a different advise call; double-unadvise; unadvising after the COM server terminated; wrong interface class for the cookie.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

AI-assisted analysis of java-native-access/jna@d036ad9781 (2026-09-12). Data as JSON: /api/errors/52af1559fc5c82f2. Report an issue: GitHub.

Appendix: source

Thrown at contrib/platform/src/com/sun/jna/platform/win32/COM/util/ProxyObject.java:350

            if (null == comInterfaceAnnotation) {
                throw new COMException(
                        "unadvise: Interface must define a value for iid via the ComInterface annotation");
            }
            IID iid = this.getIID(comInterfaceAnnotation);

            final ConnectionPoint rawCp = this.fetchRawConnectionPoint(iid);

            HRESULT hr = rawCp.Unadvise(((ComEventCallbackCookie) cookie).getValue());

            rawCp.Release();
            COMUtils.checkRC(hr);

        } catch (RuntimeException e) {
            // Do not rewrap COMException
            if (e instanceof COMException) {
                throw e;
            } else {
                throw new COMException("Error occured in unadvise when trying to disconnect the listener from " + this, e);
            }
        }
    }

    // --------------------- IDispatch ------------------------------
    @Override
    public <T> void setProperty(String name, T value) {
        DISPID dispID = resolveDispId(this.getRawDispatch(), name);
        setProperty(dispID, value);
    }

    @Override
    public <T> void setProperty(DISPID dispId, T value) {
        assert COMUtils.comIsInitialized() : "COM not initialized";

        VARIANT v = Convert.toVariant(value);
        WinNT.HRESULT hr = this.oleMethod(OleAuto.DISPATCH_PROPERTYPUT, null, this.getRawDispatch(), dispId, v);
        Convert.free(v, value); // Free value allocated by Convert#toVariant

View on GitHub (pinned to d036ad9781)