java-native-access/jna · error · IllegalArgumentException

Wrong array size !

Error message

Wrong array size !

What it means

ARRAYDESC's full constructor takes an rgbounds array that must have exactly one SAFEARRAYBOUND per declared dimension slot (the embedded fixed-size array). If the supplied array length does not match the fixed-size rgbounds field length, IllegalArgumentException 'Wrong array size !' is thrown.

Solutions

1. Pass exactly as many SAFEARRAYBOUND entries as the ARRAYDESC.rgbounds field expects (allocate the fixed-size array via new SAFEARRAYBOUND[1])
2. Set cDims consistently with the bounds array
3. Build ARRAYDESC by assigning fields directly if you need a different number of bounds
4. Validate rgbounds.length before construction

Example fix

// before
ARRAYDESC d = new ARRAYDESC(tdesc, cDims, new SAFEARRAYBOUND[0]);
// after
SAFEARRAYBOUND[] bounds = (SAFEARRAYBOUND[]) new SAFEARRAYBOUND().toArray(1);
bounds[0].lLbound = 0;
bounds[0].cElements = 10;
ARRAYDESC d = new ARRAYDESC(tdesc, (short) 1, bounds);

if (rgbounds == null || rgbounds.length != 1) throw new IllegalArgumentException("ARRAYDESC expects exactly " + 1 + " bound(s)");

try {
    new ARRAYDESC(tdescElem, cDims, rgbounds);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("Wrong array size")) { /* reallocate bounds array */ }
    else throw e;
}

When it happens

Trigger: Constructing new OaIdl.ARRAYDESC(tdescElem, cDims, rgbounds) where rgbounds.length does not equal the structure's fixed rgbounds field length (1) — e.g. passing an empty array or more than one bound for the declared dimensions.

Common situations: Building multi-dimensional array type descriptors for IDispatch::GetTypeInfo; passing a dynamically-sized bounds list without matching the fixed field; forgetting to allocate SAFEARRAYBOUND entries.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Supplied Array has no dimensions.
• advise: Interface must define a value for either iid via…
• advise: Interface must define a value for either iid via…
• Bad volume GUID path format:
• Byte boundary must be positive

AI-assisted analysis of java-native-access/jna@d036ad9781 (2026-09-12). Data as JSON: /api/errors/bb2793474d6ffdc0. Report an issue: GitHub.

Appendix: source

Thrown at contrib/platform/src/com/sun/jna/platform/win32/OaIdl.java:1839

        public ARRAYDESC(Pointer pointer) {
            super(pointer);
            this.read();
        }

        /**
         * @param tdescElem
         *            C type : TYPEDESC<br>
         * @param cDims dimensions
         * @param rgbounds
         *            [size_is]<br>
         *            C type : SAFEARRAYBOUND[1]
         */
        public ARRAYDESC(TYPEDESC tdescElem, short cDims, SAFEARRAYBOUND rgbounds[]) {
            this.tdescElem = tdescElem;
            this.cDims = cDims;
            if (rgbounds.length != this.rgbounds.length)
                throw new IllegalArgumentException("Wrong array size !");
            this.rgbounds = rgbounds;
        }

        public static class ByReference extends ARRAYDESC implements
                Structure.ByReference {

        };
    }

    @FieldOrder({"pparamdescex", "wParamFlags"})
    public static class PARAMDESC extends Structure {
        public static class ByReference extends PARAMDESC implements
                Structure.ByReference {
        }

        // replaced PARAMDESCEX.ByReference with Pointer
        // because of JNA 4 has a problem with ByReference
        public Pointer pparamdescex;

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