Java fuzzer crashes when referencing classes not in the classpath

[IlyaMuravjov]

Description

Fuzzer crushes when method under test directly or indirectly accepts value of type X (indirectly meaning that it accepts some Y whose creation directly or indirectly may involve using X) such that:

• X is not a common reference type that has a custom value provider (e.g. List, Map)
• X doesn't have a public constructor
• there's a class Z such that:
  • it's reachable from user code (not necessarily from class under test)
  • it has a non-static method returning X
  • it has a constructor that accepts class that is not on the classpath

Although, it may seem that this bug requires unlikely combination of tested program properties, as bolded text shows it's enough for some unrelated parts of the project to posses these properties, making this bug exceedingly likelier to occur as the project under test gets larger (in fact, it happened for me on the very first method in spring-boot-testing that I tried to generate tests for to check performance of #2583).

To Reproduce

1. Use UtBot version from Introduce object creation using builders for fuzzers #2583
2. Create Java project (I used Java 11)
3. Add implementation("org.hibernate:hibernate-validator:8.0.1.Final") dependency (can also be reproduced with other libraries)
4. Add the following classes
5. Generate tests for the ClassUnderTest (optionally use 100% fuzzing)

public class ClassUnderTest {
    public static int getLength(CharSequence charSequence) {
        return charSequence.length();
    }
}

public class UnrelatedClass {
    public static void useHibernateValidator(HibernateValidator hibernateValidator) { }
}

Expected behavior

Test generation completes without errors.

Actual behavior

Fuzzer crashes (in this particular case fuzzer managed to cover the method under test before crashing, but we can't rely on it)

Visual proofs

21:25:21.574 | INFO  | JavaLanguage              | Fuzzing is stopped because of an error
java.lang.NoClassDefFoundError: jakarta/el/ExpressionFactory
	at java.lang.Class.getDeclaredConstructors0(Native Method) ~[?:?]
	at java.lang.Class.privateGetDeclaredConstructors(Class.java:3137) ~[?:?]
	at java.lang.Class.getDeclaredConstructors(Class.java:2357) ~[?:?]
	at org.utbot.framework.plugin.api.ClassId.getAllConstructors(Api.kt:1076) ~[utbot-framework-api-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.providers.ObjectValueProvider$generate$1.invokeSuspend(Objects.kt:72) ~[utbot-java-fuzzing-2023.09-SNAPSHOT.jar:?]
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequenceBuilderIterator.hasNext(SequenceBuilder.kt:129) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at org.utbot.fuzzing.ValueProvider$Combined$generate$1.invokeSuspend(Providers.kt:231) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequenceBuilderIterator.hasNext(SequenceBuilder.kt:129) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at org.utbot.fuzzing.ValueProvider$Fallback.generate(Providers.kt:161) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.ValueProvider$Combined$generate$1.invokeSuspend(Providers.kt:198) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequenceBuilderIterator.hasNext(SequenceBuilder.kt:129) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.FlatteningSequence$iterator$1.ensureItemIterator(Sequences.kt:316) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.FlatteningSequence$iterator$1.hasNext(Sequences.kt:303) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequencesKt___SequencesKt.toCollection(_Sequences.kt:787) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequencesKt___SequencesKt.toMutableList(_Sequences.kt:817) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlin.sequences.SequencesKt___SequencesKt.toList(_Sequences.kt:808) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at org.utbot.fuzzing.FuzzingApi$produce$seeds$1.apply(Api.kt:427) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi$produce$seeds$1.apply(Api.kt:426) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at java.util.HashMap.computeIfAbsent(HashMap.java:1134) ~[?:?]
	at org.utbot.fuzzing.FuzzingApi.produce(Api.kt:426) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.fuzz(Api.kt:399) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.reduce(Api.kt:519) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.produce(Api.kt:437) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.fuzz(Api.kt:399) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.fuzz$fuzzOne(Api.kt:331) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.fuzz(Api.kt:350) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi.access$fuzz(Api.kt:1) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at org.utbot.fuzzing.FuzzingApi$fuzz$2.invokeSuspend(Api.kt) ~[utbot-fuzzing-2023.09-SNAPSHOT.jar:?]
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) ~[kotlin-stdlib-1.8.10.jar:1.8.10-release-430(1.8.10)]
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:284) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:85) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source) ~[kotlinx-coroutines-core-jvm-1.6.3.jar:?]
	at org.utbot.common.ConcurrencyKt.runBlockingWithCancellationPredicate(Concurrency.kt:38) ~[utbot-core-2023.09-SNAPSHOT.jar:?]
	at org.utbot.framework.plugin.api.TestCaseGenerator$generate$2$3.invoke(TestCaseGenerator.kt:194) ~[utbot-framework-2023.09-SNAPSHOT.jar:?]
	at org.utbot.framework.plugin.api.TestCaseGenerator$generate$2$3.invoke(TestCaseGenerator.kt:193) ~[utbot-framework-2023.09-SNAPSHOT.jar:?]
	at org.utbot.common.ConcurrencyKt.runIgnoringCancellationException(Concurrency.kt:47) ~[utbot-core-2023.09-SNAPSHOT.jar:?]
	at org.utbot.framework.plugin.api.TestCaseGenerator.generate(TestCaseGenerator.kt:193) ~[utbot-framework-2023.09-SNAPSHOT.jar:?]
	at org.utbot.framework.process.EngineProcessMainKt$setup$4.invoke(EngineProcessMain.kt:127) ~[utbot-framework-2023.09-SNAPSHOT.jar:?]
	at org.utbot.framework.process.EngineProcessMainKt$setup$4.invoke(EngineProcessMain.kt:112) ~[utbot-framework-2023.09-SNAPSHOT.jar:?]
	at org.utbot.rd.IdleWatchdog$measureTimeForActiveCall$1$2$1.invoke(ClientProcessUtil.kt:115) ~[utbot-rd-2023.09-SNAPSHOT.jar:?]
	at org.utbot.rd.IdleWatchdog.wrapActive(ClientProcessUtil.kt:88) ~[utbot-rd-2023.09-SNAPSHOT.jar:?]
	at org.utbot.rd.IdleWatchdog$measureTimeForActiveCall$1.invoke(ClientProcessUtil.kt:114) ~[utbot-rd-2023.09-SNAPSHOT.jar:?]
	at com.jetbrains.rd.framework.IRdEndpoint$set$1.invoke(TaskInterfaces.kt:182) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.IRdEndpoint$set$1.invoke(TaskInterfaces.kt:182) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.impl.RdCall.onWireReceived(RdTask.kt:362) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.MessageBroker$invoke$2$2.invoke(MessageBroker.kt:57) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.MessageBroker$invoke$2$2.invoke(MessageBroker.kt:56) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.impl.ProtocolContexts.readMessageContextAndInvoke(ProtocolContexts.kt:148) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.MessageBroker$invoke$2.invoke(MessageBroker.kt:56) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.framework.MessageBroker$invoke$2.invoke(MessageBroker.kt:54) ~[rd-framework-2023.1.2.jar:?]
	at com.jetbrains.rd.util.threading.SingleThreadSchedulerBase.queue$lambda-3(SingleThreadScheduler.kt:41) ~[rd-core-2023.1.2.jar:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.lang.ClassNotFoundException: jakarta.el.ExpressionFactory
	at java.net.URLClassLoader.findClass(URLClassLoader.java:476) ~[?:?]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:589) ~[?:?]
	at org.utbot.common.FallbackClassLoader.loadClass(FallbackClassLoader.kt:41) ~[utbot-core-2023.09-SNAPSHOT.jar:?]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[?:?]
	... 61 more