pinpoint-apm/pinpoint · warning

unexpected {} invoke count {}

Error message

unexpected {} invoke count {}

What it means

LambdaFactoryClassAdaptor.transform() replaces java/lang/invoke/LambdaMetafactory invocations with Pinpoint's LambdaFactory when instrumenting lambda call sites. It expects exactly one transformed invocation; if methodInstReplacer.getTransformCount() != 1, it warns 'unexpected {} invoke count {}' so the (possibly wrong) bytecode can be inspected. The class is still returned, but the lambda instrumentation may be incomplete or wrong.

Source

Thrown at agent-module/profiler-optional/profiler-optional-jdk8/src/main/java/com/navercorp/pinpoint/profiler/instrument/lambda/LambdaFactoryClassAdaptor.java:72

            return new LambdaClassJava8();
        }
    }

    public byte[] transform(byte[] bytes, LambdaClass lambdaClass) {
        Objects.requireNonNull(bytes, "bytes");

        final ClassReader reader = new ClassReader(bytes);
        final ClassWriter writer = new ClassWriter(reader, ClassWriter.COMPUTE_FRAMES);
        final List<MethodInsn> methodInsnList = lambdaClass.getMethodInsnList();
        final MethodInstReplacer methodInstReplacer = new MethodInstReplacer(writer, methodInsnList);
        reader.accept(methodInstReplacer, 0);

        if (!LAMBDA_FACTORY_CLASS_NAME.equals(methodInstReplacer.getClassName())) {
            throw new IllegalArgumentException("unexpected class " + methodInstReplacer.getClassName());
        }

        if (methodInstReplacer.getTransformCount() != 1) {
            logger.warn("unexpected {} invoke count {}", methodInsnList, methodInstReplacer.getTransformCount());
            // dump bytecode
        }
        return writer.toByteArray();
    }
}

View on GitHub (pinned to 744c3d3075)

Solutions

1. Inspect the dumped/original bytecode of the failing class to count LambdaMetafactory invokes
2. Restrict the interceptor/transform scope so classes with multiple lambdas are excluded
3. Update Pinpoint to a version with multi-lambda handling for lambda instrumentation
4. Report the class and bytecode to Pinpoint maintainers if it triggers spuriously

Example fix

// before (transform config applying to a multi-lambda class)
transform("com/example/ManyLambdas")
// after (exclude)
if (className.equals("com/example/ManyLambdas")) return null; // skip lambda instrumentation

// count lambda factory call sites before transform; int invocations = countInvokeInstructions(bytes, "java/lang/invoke/LambdaMetafactory"); if (invocations != 1) skip or handle multi-lambda;

try { writer = adapt(reader); } catch (Exception e) { logger.warn("lambda transform failed for {}, returning original bytes", className); return null; }

When it happens

Trigger: Instrumenting a class whose lambda metafactory invoke instruction count is not exactly 1 — e.g. a class with multiple lambdas, zero lambdas matched, or a bytecode pattern the replacer did not anticipate.

Common situations: Newer compiler output (different invokedynamic handling) targeting the JDK8 adapter; a plugin interceptor attaching to a lambda-heavy class; Pinpoint instrumentation classes that contain several lambda factories.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• source and advice class node must not be null.
• No methods are intercepted. target:{}, interceptor:{}, metho
• No methods are intercepted. target:{}, interceptor:{}, metho
• unexpected class ${className}
• ${name} define fail Caused by:${e.getMessage()}

AI-assisted analysis of pinpoint-apm/pinpoint@744c3d3075 (2026-09-07). Data as JSON: /api/errors/606af8ff61d93ac1. Report an issue: GitHub.