Java supplier interface with org.powermock.reflect.exceptions.MethodNotFoundException

Question

I have mock a https://github.com/elastic/elasticsearch/blob/master/core/src/main/java/org/elasticsearch/client/transport/TransportClient.java with Powermockito, before it works, but since the code chanage and add below code:

NetworkModule networkModule = new NetworkModule(settings, true, pluginsService.filterPlugins(NetworkPlugin.class), threadPool,
                bigArrays, circuitBreakerService, namedWriteableRegistry, xContentRegistry, networkService);
            final Transport transport = networkModule.getTransportSupplier().get();

the code alway fail at getTransportSupplier().get(), the throws exception:

Caused by: org.powermock.reflect.exceptions.MethodNotFoundException: No methods matching the name(s) get were found in the class hierarchy of class java.lang.Object.
    at org.powermock.reflect.internal.WhiteboxImpl.getMethods(WhiteboxImpl.java:1720)
    at org.powermock.reflect.internal.WhiteboxImpl.getMethods(WhiteboxImpl.java:1745)
    at org.powermock.reflect.internal.WhiteboxImpl.getBestMethodCandidate(WhiteboxImpl.java:983)
    at org.powermock.core.MockGateway$MockInvocation.findMethodToInvoke(MockGateway.java:317)
    at org.powermock.core.MockGateway$MockInvocation.init(MockGateway.java:356)
    at org.powermock.core.MockGateway$MockInvocation.<init>(MockGateway.java:307)
    at org.powermock.core.MockGateway.doMethodCall(MockGateway.java:142)
    at org.powermock.core.MockGateway.methodCall(MockGateway.java:125)
    at org.elasticsearch.client.transport.TransportClient.buildTemplate(TransportClient.java:162)

networkModule.getTransportSupplier() returns Supplier.

here is code from networkModule: https://github.com/elastic/elasticsearch/blob/master/core/src/main/java/org/elasticsearch/common/network/NetworkModule.java any idea why?

Answer 1

I think this is a bug with Powermock.

See that entry in their issues database; which shows the same stack trace (although for some different target). But close enough.

So, chances are, this will be fixed at some point. Or not.

Long story, short rant: I have seen too many such problems with PowerMock; thus I decided at some point that I rather fix my broken designs; instead of using the PowerMock hammer. In my experience, when we talk about "our own code"; then we simply create easy-to-test code; and then we do not need PowerMock any more. Seriously, that works. When you create your own classes, and you need PowerMock to test that; then you did something wrong! And as soon as you stop using PowerMock; you stop spending time on problems that have nothing to do with your product.

Anyway, your option space is:

• Subscribe to that defect; and try to get some attention to it; the more people go there and give "me too", the more likely something will happen.
• Look into your design and have a closer look why you need PowerMock(ito). And then decide if you would benefit from eliminating this requirement by changing your production code.