java-native-access/jna · warning · IllegalStateException

NOT IMPLEMENTED: getValue

Error message

NOT IMPLEMENTED: getValue(%s) (Array: %b, Count: %d)

What it means

This IllegalStateException is thrown by Winevt.EVT_VARIANT.setValue when setValue() is called on a variant whose EvtVarType falls into a branch the library has not implemented for writing — file time, event handle, SYSTEMTIME, GUID, SID, size_t, or the default catch-all. The message includes the type, whether the variant is an array, and the count to aid diagnosis. It signals an incomplete library feature, not bad input per se.

Solutions

1. Do not call setValue() on these variant types — restructure code so the value is set through the native API (e.g. EvtSetChannelConfigProperty with a properly built EVT_VARIANT) or leave the property unchanged
2. Convert the value to a supported representation (e.g. byte[]) only if the type branch actually supports it; otherwise avoid the write
3. Upgrade JNA to the newest version to check whether write support for the type was added
4. Catch IllegalStateException around setValue to detect unsupported types at runtime and skip/logging the property

Example fix

// before
if (prop.type == EvtVarTypeGuid) { variant.setValue(guid); }
// after
if (prop.type == EvtVarTypeGuid) {
    throw new UnsupportedOperationException("Writing GUID-valued properties is not supported by EVT_VARIANT.setValue");
}

switch (variant.type) {
    case Winevt.EvtVarTypeFileTime:
    case Winevt.EvtVarTypeEvtHandle:
    case Winevt.EvtVarTypeSysTime:
    case Winevt.EvtVarTypeGuid:
    case Winevt.EvtVarTypeSid:
    case Winevt.EvtVarTypeSizeT:
        throw new IllegalStateException("setValue not supported for " + variant.type);
}

boolean isSettable(EVT_VARIANT v) {
    switch (v.type) {
        case Winevt.EvtVarTypeFileTime: case Winevt.EvtVarTypeEvtHandle:
        case Winevt.EvtVarTypeSysTime: case Winevt.EvtVarTypeGuid:
        case Winevt.EvtVarTypeSid: case Winevt.EvtVarTypeSizeT:
            return false;
        default: return true;
    }
}

try {
    variant.setValue(val);
} catch (IllegalStateException e) {
    log.info("Skipping unsupported variant write: " + e.getMessage());
}

When it happens

Trigger: Calling setValue() on an EVT_VARIANT whose type is EvtVarTypeFileTime, EvtVarTypeEvtHandle, EvtVarTypeSysTime, EvtVarTypeGuid, EvtVarTypeSid, EvtVarTypeSizeT or any unhandled type, whether scalar or array (isArray()/Count are echoed in the message).

Common situations: Attempting to modify channel/config properties that hold GUIDs or timestamps; writing back values read from event XML that were rendered as WinNT.HANDLE, FILETIME or GUID structures; running a JNA version where write support for these types was never added.

Related errors

• Maximum argument count is
• must be set from BOOL/BOOL[]
• must be set from byte[]
• must be set from byte/byte[]
• must be set from double/double[]

AI-assisted analysis of java-native-access/jna@d036ad9781 (2026-09-12). Data as JSON: /api/errors/a3c6cbb4e065ca97. Report an issue: GitHub.

Appendix: source

Thrown at contrib/platform/src/com/sun/jna/platform/win32/Winevt.java:459

                        if (value.getClass().isArray() && value.getClass().getComponentType() == byte.class) {
                            Type = type.ordinal();
                            Memory mem = new Memory(((byte[]) value).length * 1);
                            mem.write(0, (byte[]) value, 0, ((byte[]) value).length);
                            holder = mem;
                            Count = 0;
                            field1.writeField("pointerValue", mem);
                        } else {
                            throw new IllegalArgumentException(type.name() + " must be set from byte[]");
                        }
                        break;
                    case EvtVarTypeFileTime:
                    case EvtVarTypeEvtHandle:
                    case EvtVarTypeSysTime:
                    case EvtVarTypeGuid:
                    case EvtVarTypeSid:
                    case EvtVarTypeSizeT:
                    default:
                        throw new IllegalStateException(String.format("NOT IMPLEMENTED: getValue(%s) (Array: %b, Count: %d)", type, isArray(), Count));
                }
            }
            write();
        }

        /**
         * @return value contained in the EVT_VARIANT
         */
        public Object getValue() {
            EVT_VARIANT_TYPE type = getVariantType();
            switch (type) {
                case EvtVarTypeAnsiString:
                    return isArray() ? field1.getPointer().getPointer(0).getStringArray(0, Count) : field1.getPointer().getPointer(0).getString(0);
                case EvtVarTypeBoolean:
                    if (isArray()) {
                        int[] rawValue = field1.getPointer().getPointer(0).getIntArray(0, Count);
                        WinDef.BOOL[] result = new WinDef.BOOL[rawValue.length];
                        for (int i = 0; i < result.length; i++) {

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