Method threw 'java.lang.IllegalArgumentException' exception. how can I set private final value using java reflection

Question

I am writing a junit code for some method. and in this method need to set private final value for complete code coverage. But I am getting Method threw 'java.lang.IllegalArgumentException' exception

 @Test
    void partitionProcessorTest() throws Exception {
     
        EventData eventData = new EventData(body);
        
        //  below line code for finding nested class
        Class<?> []clazz = eventData.getClass().getDeclaredClasses();

        // and this is my inner class object 
        Class<?> inner = clazz[0];

        // this is my inner class constructer 
        Constructor<?> constructor = inner.getDeclaredConstructor();
        constructor.setAccessible(true);
        Object obj = constructor.newInstance();

        // this is my sequenceNumber field. which is private final Long type, in inner class 
        Field f = inner.getDeclaredField("sequenceNumber");
        f.setAccessible(true);

        //I am trying to remove final keyword from declared field in my inner class
        Field filed= Field.class.getDeclaredField("modifiers");
        filed.setAccessible(true);
        filed.setInt(f, f.getModifiers() & ~Modifier.FINAL);
       
        // but iam getting exception, where i am donig mistake please suggest me  
        // In this line i am getting exception --> f.setLong(eventData , 10l);
        try{
        f.setLong(eventData , 10l);
        }
        catch(Throwable e)
        {
        e.printStackTrace();
        }
        System.out.println(obj);
    }

and here is my Exception logs

java.lang.IllegalArgumentException: Can not set java.lang.Long field com.azure.messaging.eventhubs.EventData$SystemProperties.sequenceNumber to (long)10 at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167) at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:195) at sun.reflect.UnsafeObjectFieldAccessorImpl.setLong(UnsafeObjectFieldAccessorImpl.java:120) at java.lang.reflect.Field.setLong(Field.java:986) at com.tdchannels.sdk.ms.channel.services.impl.EventHubConsumerServiceImplTest.partitionProcessorTest(EventHubConsumerServiceImplTest.java:69) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:675) at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60) at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:125) at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:132) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:124) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:74) at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115) at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105) at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:104) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:62) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:43) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:35) at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104) at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:202) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:198) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:69) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80) at java.util.ArrayList.forEach(ArrayList.java:1249) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80) at java.util.ArrayList.forEach(ArrayList.java:1249) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32) at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:170) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:154) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:90) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:102) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:82) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:78) at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:61) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24) at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32) at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93) at com.sun.proxy.$Proxy2.stop(Unknown Source) at org.gradle.api.internal.tasks.testing.worker.TestWorker.stop(TestWorker.java:132) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24) at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:175) at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:157) at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63) at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)

==========================================================================

java.lang.NullPointerException at com.azure.messaging.eventhubs.models.EventContext.updateCheckpoint(EventContext.java:101) at com.tdchannels.sdk.ms.channel.services.EventHubConsumerThread.lambda$new$0(EventHubConsumerThread.java:106) at com.tdchannels.sdk.ms.channel.services.impl.EventHubConsumerServiceImplTest.partitionProcessorTest(EventHubConsumerServiceImplTest.java:99)

Please edit the question and include the stack trace as text, not as image. — Turing85
– Turing85, Commented Dec 28, 2020 at 12:57
The stack trace is pointing at a lambda which is nowhere in your pasted code. Therefore this question cannot be answered. — rzwitserloot
– rzwitserloot, Commented Dec 28, 2020 at 13:03
As a separate point, that Field object is just a copy of the state of that field, setting its modifiers field to take the final flag out doesn't do anything. — rzwitserloot
– rzwitserloot, Commented Dec 28, 2020 at 13:04

Robert Ellis · Accepted Answer · 2020-12-29 05:37:14Z

1

Can not set java.lang.Long field com.azure.messaging.eventhubs.EventData$SystemProperties.sequenceNumber to (long)10 at

as per the trace you are setting the long primitive to Long object try setting the Object Long instead of long

Like this

Long aLong = Long.valueOf(100);
try{
    f.setLong(eventData , aLong);
}
catch(Throwable e)
{
    e.printStackTrace();
}

answered Dec 29, 2020 at 5:37

Robert Ellis

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2 Comments

Sonu soni Over a year ago

--> I am getting same exception.

Robert Ellis Over a year ago

can u update with the error after this code

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