public class ExampleString { public void stringNewMethod() { var text = "Hello!\nThis is String used with indent method."; text = text.indent(-3); System.out.println(text); text = text.indent(-5); System.out.println(text); } } 

var adn String::indent nethod is used (12), compiled and executed with JDK-13 WARNING: sun.reflect.Reflection.getCallerClass is not supported. This will impact performance. 16:03:45.474 | INFO | AllInMemoryClassProvider | Loaded: 2 path entries, 46 classes, 194922 bytes 16:03:46.718 | INFO | UtBotTestCaseGenerator | |> Resuming method ExampleString.stringNewMethod() 16:03:47.189 | ERROR | UtBotSymbolicEngine | Test generation failed on stmt $b0 = r0.<java.lang.String: byte coder>, symbolic stack trace: <java.lang.String: boolean isLatin1()> <java.lang.String: java.util.stream.Stream lines()> <java.lang.String: java.lang.String indent(int)> <ExampleString: void stringNewMethod()> java.lang.IllegalStateException: No such field byte coder found in org.utbot.engine.overrides.strings.UtString at org.utbot.engine.Hierarchy.chunkIdForField(Hierarchy.kt:33) ~[utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine.createFieldOrMock(UtBotSymbolicEngine.kt:2217) ~[utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine.resolve(UtBotSymbolicEngine.kt:2027) ~[utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine.traverseAssignStmt(UtBotSymbolicEngine.kt:1069) ~[utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine.traverseStmt(UtBotSymbolicEngine.kt:696) ~[utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine$traverseImpl$1.invokeSuspend(UtBotSymbolicEngine.kt:551) [utbot-cli-2022.7.jar:?] at org.utbot.engine.UtBotSymbolicEngine$traverseImpl$1.invoke(UtBotSymbolicEngine.kt) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.flow.SafeFlow.collectSafely(Builders.kt:61) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.flow.AbstractFlow.collect(Flow.kt:212) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.flow.FlowKt__EmittersKt$onStart$$inlined$unsafeFlow$1.collect(SafeCollector.common.kt:120) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.flow.FlowKt__EmittersKt$onCompletion$$inlined$unsafeFlow$1.collect(SafeCollector.common.kt:114) [utbot-cli-2022.7.jar:?] at org.utbot.framework.plugin.api.UtBotTestCaseGenerator$generateForSeveralMethods$4$1$1.invokeSuspend(UtBotTestCaseGenerator.kt:447) [utbot-cli-2022.7.jar:?] at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:274) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:84) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:59) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:38) [utbot-cli-2022.7.jar:?] at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source) [utbot-cli-2022.7.jar:?] at org.utbot.common.ConcurrencyKt.runBlockingWithCancellationPredicate(Concurrency.kt:38) [utbot-cli-2022.7.jar:?] at org.utbot.framework.plugin.api.UtBotTestCaseGenerator$generateForSeveralMethods$4.invoke(UtBotTestCaseGenerator.kt:279) [utbot-cli-2022.7.jar:?] at org.utbot.framework.plugin.api.UtBotTestCaseGenerator$generateForSeveralMethods$4.invoke(UtBotTestCaseGenerator.kt:56) [utbot-cli-2022.7.jar:?] at org.utbot.common.ConcurrencyKt.runIgnoringCancellationException(Concurrency.kt:47) [utbot-cli-2022.7.jar:?] at org.utbot.framework.plugin.api.UtBotTestCaseGenerator.generateForSeveralMethods(UtBotTestCaseGenerator.kt:278) [utbot-cli-2022.7.jar:?] at org.utbot.framework.plugin.api.UtBotTestCaseGenerator.generateForSeveralMethods$default(UtBotTestCaseGenerator.kt:265) [utbot-cli-2022.7.jar:?] at org.utbot.cli.GenerateTestsAbstractCommand.generateTestCases(GenerateTestsAbstractCommand.kt:163) [utbot-cli-2022.7.jar:?] at org.utbot.cli.GenerateTestsCommand.run(GenerateTestsCommand.kt:102) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:204) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:213) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:17) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.core.CliktCommand.parse(CliktCommand.kt:396) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.core.CliktCommand.parse$default(CliktCommand.kt:393) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:411) [utbot-cli-2022.7.jar:?] at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:436) [utbot-cli-2022.7.jar:?] at org.utbot.cli.ApplicationKt.main(Application.kt:31) [utbot-cli-2022.7.jar:?] 16:03:47.236 | INFO | Summarization | Diversity execution path percentage: 100 16:03:47.236 | INFO | Summarization | No execution traces found in test case for method ExampleString, public void stringNewMethod() { java.io.PrintStream $r0, $r1; ExampleString r2; java.lang.String r3, r4, r5; r2 := @this: ExampleString; r3 = "Hello Baeldung!\nThis is Java 12 article."; r4 = virtualinvoke r3.<java.lang.String: java.lang.String indent(int)>(-4); $r0 = <java.lang.System: java.io.PrintStream out>; virtualinvoke $r0.<java.io.PrintStream: void println(java.lang.String)>(r4); r5 = virtualinvoke r4.<java.lang.String: java.lang.String indent(int)>(-10); $r1 = <java.lang.System: java.io.PrintStream out>; virtualinvoke $r1.<java.io.PrintStream: void println(java.lang.String)>(r5); return; }