pinpoint-apm/pinpoint · error · IllegalArgumentException

null parameterType not supported

Error message

null parameterType not supported

What it means

TransformTemplate.transform rejects a parameterTypes array that contains null entries. A null element is not a real Class token, so before deeper validation the method throws IllegalArgumentException with this message.

Source

Thrown at agent-module/bootstraps/bootstrap-core/src/main/java/com/navercorp/pinpoint/bootstrap/instrument/transformer/TransformTemplate.java:90

////        if (ParameterUtils.hasNull(parameters)) {
////            throw new IllegalArgumentException("null parameter not supported");
////        }
//
//        final Class<?>[] parameterType = ParameterUtils.toClass(parameters);
//        // commons-lang
//        // ConstructorUtils.getMatchingAccessibleConstructor()
//
//        transform(className, transformCallbackClass, parameters, parameterType);
//    }

    @Override
    public void transform(String className, Class<? extends TransformCallback> transformCallbackClass, Object[] parameters, Class<?>[] parameterTypes) {
        Objects.requireNonNull(className, "className");
        Objects.requireNonNull(transformCallbackClass, "transformCallbackClass");

        TransformCallbackChecker.validate(transformCallbackClass, parameterTypes);
        if (ParameterUtils.hasNull(parameterTypes)) {
            throw new IllegalArgumentException("null parameterType not supported");
        }
        ParameterUtils.checkParameterType(parameterTypes);


        final Matcher matcher = Matchers.newClassNameMatcher(className);

        // release class reference
        final String transformCallbackName = transformCallbackClass.getName();
        this.instrumentContext.addClassFileTransformer(matcher, transformCallbackName, parameters, parameterTypes);
    }

    @Override
    public void transform(String className, Class<? extends TransformCallback> transformCallbackClass, TransformCallbackParameters params) {
        Object[] parameters = params.values();
        Class<?>[] parameterTypes = params.types();
        this.transform(className, transformCallbackClass, parameters, parameterTypes);
    }
}

View on GitHub (pinned to 744c3d3075)

Solutions

1. Ensure every element of parameterTypes is a non-null Class before calling transform
2. Size the array to the actual number of parameters to avoid trailing null slots
3. Use a helper (ParameterUtils.hasNull) in your own code to pre-validate

Example fix

// before
Class<?>[] types = new Class<?>[2];
types[0] = String.class; // types[1] is null
transformer.transform("Foo", Cb.class, new Object[]{"a"}, types); // throws
// after
Class<?>[] types = new Class<?>[]{String.class};
transformer.transform("Foo", Cb.class, new Object[]{"a"}, types);

boolean hasNullType = parameterTypes == null || Arrays.asList(parameterTypes).contains(null);
if (hasNullType) throw new IllegalArgumentException("parameterTypes must not contain null");

try {
    transformer.transform(name, cb, params, types);
} catch (IllegalArgumentException e) {
    if ("null parameterType not supported".equals(e.getMessage())) {
        logger.error("parameterTypes array contains null; rebuild it with concrete Class tokens", e);
    } else { throw e; }
}

When it happens

Trigger: Calling transform(className, callbackClass, parameters, parameterTypes) where the parameterTypes array itself contains a null element (e.g. built by conditional code that forgot to assign a Class).

Common situations: Constructing the Class[] array dynamically with unassigned slots; passing a mix of typed and untyped constructor arguments; converting a varargs list that included nulls.

Related errors

• transformCallbackClass must be static inner class. class:
• Invalid time unit provided.
• unsupported type:
• constructor not found
• handler

AI-assisted analysis of pinpoint-apm/pinpoint@744c3d3075 (2026-09-07). Data as JSON: /api/errors/748fcb22bae1cd98. Report an issue: GitHub.