[질문 템플릿]1. 강의 내용과 관련된 질문인가요? (예/아니오)2. 인프런의 질문 게시판과 자주 하는 질문에 없는 내용인가요? (예/아니오)3. 질문 잘하기 메뉴얼을 읽어보셨나요? (예/아니오)[질문 내용]싱글톤 컨테이너 강의중 PDF 파일에 싱글턴 싱글톤 이 섞여서 사용되는데 영어라서 한글로 표현할때 싱글턴이나 싱글톤이나 같긴한거같은데 통일되게 사용을 안한 이유같은게 있지는 않겠죠??

1. getBean 메소드의 반환값은 해당 빈의 객체인가요?  MemberRepository memberRepository = ac.getBean("memberRepository1", MemberRepository.class); 여기에서 memberRepository에는 MemoryMemberRepository의 객체가 들어가나요? (혹은 참조값)   2. MemberRepository memberRepository = ac.getBean("memberRepository1", MemberRepository.class);     assertThat(memberRepository).isInstanceOf(MemberRepository.class);   memberRepository가 MemberRepository.class의 인스턴스라는게 이해가 잘 안됩니다. MemoryMemberRepository.class의 인스턴스 아닌가요? memberRepository에 MemoryMemberRepository의 객체가 들어간다면  MemoryMemberRepository는 MemberRepository의 구현체이므로 MemberRepository의 인스턴스로 보는 건가요? 

WriteLock() 의 desired변수 초기화할때 LThreadId << 16 연산으로 인해 앞 16비트가 0이라는것이 보장되는데도 WRITE_THREAD_MASK로 &연산을 해준것은 가독성 때문이 맞을까요?

선생님~ 선생님이 git에 올려주신 _post_card.html에서  $('#post-10-comment-list').prepend(responseText); 가 $("#post{post.pk}}-comment-list").prepend(responseText);로 바뀌어야 하지 않나요??    

  23:12:28.918 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating CacheAwareContextLoaderDelegate from class [org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate] 23:12:28.934 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating BootstrapContext using constructor [public org.springframework.test.context.support.DefaultBootstrapContext(java.lang.Class,org.springframework.test.context.CacheAwareContextLoaderDelegate)] 23:12:28.994 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating TestContextBootstrapper for test class [hello.hellospring.service.MemberServiceIntegrationTest] from class [org.springframework.boot.test.context.SpringBootTestContextBootstrapper] 23:12:29.014 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Neither @ContextConfiguration nor @ContextHierarchy found for test class [hello.hellospring.service.MemberServiceIntegrationTest], using SpringBootContextLoader 23:12:29.020 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [hello.hellospring.service.MemberServiceIntegrationTest]: class path resource [hello/hellospring/service/MemberServiceIntegrationTest-context.xml] does not exist 23:12:29.021 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [hello.hellospring.service.MemberServiceIntegrationTest]: class path resource [hello/hellospring/service/MemberServiceIntegrationTestContext.groovy] does not exist 23:12:29.021 [main] INFO org.springframework.test.context.support.AbstractContextLoader - Could not detect default resource locations for test class [hello.hellospring.service.MemberServiceIntegrationTest]: no resource found for suffixes {-context.xml, Context.groovy}. 23:12:29.022 [main] INFO org.springframework.test.context.support.AnnotationConfigContextLoaderUtils - Could not detect default configuration classes for test class [hello.hellospring.service.MemberServiceIntegrationTest]: MemberServiceIntegrationTest does not declare any static, non-private, non-final, nested classes annotated with @Configuration. 23:12:29.099 [main] DEBUG org.springframework.test.context.support.ActiveProfilesUtils - Could not find an 'annotation declaring class' for annotation type [org.springframework.test.context.ActiveProfiles] and class [hello.hellospring.service.MemberServiceIntegrationTest] 23:12:29.233 [main] DEBUG org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider - Identified candidate component class: file [C:\introSpring\hello-spring\out\production\classes\hello\hellospring\HelloSpringApplication.class] 23:12:29.240 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Found @SpringBootConfiguration hello.hellospring.HelloSpringApplication for test class hello.hellospring.service.MemberServiceIntegrationTest 23:12:29.444 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper - @TestExecutionListeners is not present for class [hello.hellospring.service.MemberServiceIntegrationTest]: using defaults. 23:12:29.445 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener, org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener, org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.event.ApplicationEventsTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener, org.springframework.test.context.event.EventPublishingTestExecutionListener] 23:12:29.476 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Using TestExecutionListeners: [org.springframework.test.context.web.ServletTestExecutionListener@119020fb, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@3d9f6567, org.springframework.test.context.event.ApplicationEventsTestExecutionListener@c055c54, org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener@25e2ab5a, org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener@35e5d0e5, org.springframework.test.context.support.DirtiesContextTestExecutionListener@73173f63, org.springframework.test.context.transaction.TransactionalTestExecutionListener@55562aa9, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener@655ef322, org.springframework.test.context.event.EventPublishingTestExecutionListener@7e276594, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener@3401a114, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener@5066d65f, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener@4233e892, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener@77d2e85, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener@3ecd267f, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener@58ffcbd7] 23:12:29.484 [main] DEBUG org.springframework.test.context.support.AbstractDirtiesContextTestExecutionListener - Before test class: context [DefaultTestContext@704f1591 testClass = MemberServiceIntegrationTest, testInstance = [null], testMethod = [null], testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@58fb7731 testClass = MemberServiceIntegrationTest, locations = '{}', classes = '{class hello.hellospring.HelloSpringApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}', contextCustomizers = set[org.springframework.boot.test.autoconfigure.actuate.metrics.MetricsExportContextCustomizerFactory$DisableMetricExportContextCustomizer@376a0d86, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@13df2a8c, org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@163370c2, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@35a3d49f, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@57a3e26a, org.springframework.boot.test.context.SpringBootTestArgs@1, org.springframework.boot.test.context.SpringBootTestWebEnvironment@23bb8443], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]], attributes = map['org.springframework.test.context.web.ServletTestExecutionListener.activateListener' -> true]], class annotated with @DirtiesContext [false] with mode [null]. 23:12:29.594 [main] DEBUG org.springframework.boot.ApplicationServletEnvironment - Activating profiles [] 23:12:29.595 [main] DEBUG org.springframework.test.context.support.TestPropertySourceUtils - Adding inlined properties to environment: {spring.jmx.enabled=false, org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true} . ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.6.2) 2022-01-06 23:12:30.099 INFO 16868 --- [ main] h.h.s.MemberServiceIntegrationTest : Starting MemberServiceIntegrationTest using Java 11.0.13 on DESKTOP-MUGIJNP with PID 16868 (started by tuv in C:\introSpring\hello-spring) 2022-01-06 23:12:30.100 INFO 16868 --- [ main] h.h.s.MemberServiceIntegrationTest : No active profile set, falling back to default profiles: default 2022-01-06 23:12:31.140 INFO 16868 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode. 2022-01-06 23:12:31.165 INFO 16868 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 13 ms. Found 0 JPA repository interfaces. 2022-01-06 23:12:31.980 INFO 16868 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default] 2022-01-06 23:12:32.062 INFO 16868 --- [ main] org.hibernate.Version : HHH000412: Hibernate ORM core version 5.6.3.Final 2022-01-06 23:12:32.295 INFO 16868 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.1.2.Final} 2022-01-06 23:12:32.909 INFO 16868 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2022-01-06 23:12:32.987 INFO 16868 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. 2022-01-06 23:12:33.031 INFO 16868 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect 2022-01-06 23:12:33.852 INFO 16868 --- [ main] o.h.e.t.j.p.i.JtaPlatformInitiator : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform] 2022-01-06 23:12:33.868 INFO 16868 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default' 2022-01-06 23:12:34.346 WARN 16868 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning 2022-01-06 23:12:34.872 INFO 16868 --- [ main] o.s.b.a.w.s.WelcomePageHandlerMapping : Adding welcome page: class path resource [static/index.html] 2022-01-06 23:12:35.406 INFO 16868 --- [ main] h.h.s.MemberServiceIntegrationTest : Started MemberServiceIntegrationTest in 5.808 seconds (JVM running for 7.655) 2022-01-06 23:12:35.555 INFO 16868 --- [ main] o.s.t.c.transaction.TransactionContext : Began transaction (1) for test context [DefaultTestContext@704f1591 testClass = MemberServiceIntegrationTest, testInstance = hello.hellospring.service.MemberServiceIntegrationTest@d70dbeb, testMethod = join@MemberServiceIntegrationTest, testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@58fb7731 testClass = MemberServiceIntegrationTest, locations = '{}', classes = '{class hello.hellospring.HelloSpringApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}', contextCustomizers = set[org.springframework.boot.test.autoconfigure.actuate.metrics.MetricsExportContextCustomizerFactory$DisableMetricExportContextCustomizer@376a0d86, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@13df2a8c, org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@163370c2, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@35a3d49f, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@57a3e26a, org.springframework.boot.test.context.SpringBootTestArgs@1, org.springframework.boot.test.context.SpringBootTestWebEnvironment@23bb8443], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]], attributes = map['org.springframework.test.context.web.ServletTestExecutionListener.activateListener' -> true, 'org.springframework.test.context.web.ServletTestExecutionListener.populatedRequestContextHolder' -> true, 'org.springframework.test.context.web.ServletTestExecutionListener.resetRequestContextHolder' -> true, 'org.springframework.test.context.event.ApplicationEventsTestExecutionListener.recordApplicationEvents' -> false]]; transaction manager [org.springframework.orm.jpa.JpaTransactionManager@2573b149]; rollback [true] Hibernate: select member0_.id as id1_0_, member0_.name as name2_0_ from member member0_ where member0_.name=? Hibernate: insert into member (id, name) values (null, ?) 2022-01-06 23:12:35.981 WARN 16868 --- [ main] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 23502, SQLState: 23502 2022-01-06 23:12:35.981 ERROR 16868 --- [ main] o.h.engine.jdbc.spi.SqlExceptionHelper : NULL not allowed for column "ID"; SQL statement: insert into member (id, name) values (null, ?) [23502-200] 2022-01-06 23:12:36.001 INFO 16868 --- [ main] o.s.t.c.transaction.TransactionContext : Rolled back transaction for test: [DefaultTestContext@704f1591 testClass = MemberServiceIntegrationTest, testInstance = hello.hellospring.service.MemberServiceIntegrationTest@d70dbeb, testMethod = join@MemberServiceIntegrationTest, testException = javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not execute statement, mergedContextConfiguration = [WebMergedContextConfiguration@58fb7731 testClass = MemberServiceIntegrationTest, locations = '{}', classes = '{class hello.hellospring.HelloSpringApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}', contextCustomizers = set[org.springframework.boot.test.autoconfigure.actuate.metrics.MetricsExportContextCustomizerFactory$DisableMetricExportContextCustomizer@376a0d86, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@13df2a8c, org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@163370c2, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@35a3d49f, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@57a3e26a, org.springframework.boot.test.context.SpringBootTestArgs@1, org.springframework.boot.test.context.SpringBootTestWebEnvironment@23bb8443], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]], attributes = map['org.springframework.test.context.web.ServletTestExecutionListener.activateListener' -> true, 'org.springframework.test.context.web.ServletTestExecutionListener.populatedRequestContextHolder' -> true, 'org.springframework.test.context.web.ServletTestExecutionListener.resetRequestContextHolder' -> true, 'org.springframework.test.context.event.ApplicationEventsTestExecutionListener.recordApplicationEvents' -> false]] javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not execute statement at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:154) at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181) at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:188) at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:766) at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:746) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:311) at com.sun.proxy.$Proxy90.persist(Unknown Source) at hello.hellospring.repository.JpaMemberRepository.save(JpaMemberRepository.java:19) at hello.hellospring.service.MemberService.join(MemberService.java:27) at hello.hellospring.service.MemberService$$FastClassBySpringCGLIB$$530c61b7.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:783) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:753) at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:753) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:698) at hello.hellospring.service.MemberService$$EnhancerBySpringCGLIB$$6be7ef37.join(<generated>) at hello.hellospring.service.MemberServiceIntegrationTest.join(MemberServiceIntegrationTest.java:31) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:725) at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60) at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131) at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84) at org.junit.jupiter.engine.execution.ExecutableInvoker$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:106) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37) 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$7(TestMethodTestDescriptor.java:214) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:210) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:66) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86) at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86) at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53) at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71) at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33) at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235) at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54) Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:59) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:37) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:99) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:200) at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:58) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:43) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3279) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3885) at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:84) at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:645) at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:282) at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:263) at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:317) at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:330) at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:287) at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:193) at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:123) at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:185) at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:128) at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:55) at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107) at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:760) ... 89 more Caused by: org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column "ID"; SQL statement: insert into member (id, name) values (null, ?) [23502-206] at org.h2.message.DbException.getJdbcSQLException(DbException.java:527) at org.h2.message.DbException.getJdbcSQLException(DbException.java:496) at org.h2.message.DbException.get(DbException.java:227) at org.h2.message.DbException.get(DbException.java:203) at org.h2.table.Column.validateConvertUpdateSequence(Column.java:365) at org.h2.table.Table.convertInsertRow(Table.java:917) at org.h2.command.dml.Insert.insertRows(Insert.java:167) at org.h2.command.dml.Insert.update(Insert.java:135) at org.h2.command.CommandContainer.executeUpdateWithGeneratedKeys(CommandContainer.java:246) at org.h2.command.CommandContainer.update(CommandContainer.java:167) at org.h2.command.Command.executeUpdate(Command.java:252) at org.h2.server.TcpServerThread.process(TcpServerThread.java:408) at org.h2.server.TcpServerThread.run(TcpServerThread.java:191) at java.base/java.lang.Thread.run(Thread.java:832) at org.h2.message.DbException.getJdbcSQLException(DbException.java:459) at org.h2.engine.SessionRemote.done(SessionRemote.java:611) at org.h2.command.CommandRemote.executeUpdate(CommandRemote.java:237) at org.h2.jdbc.JdbcPreparedStatement.executeUpdateInternal(JdbcPreparedStatement.java:191) at org.h2.jdbc.JdbcPreparedStatement.executeUpdate(JdbcPreparedStatement.java:152) at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61) at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197) ... 107 more 2022-01-06 23:12:36.028 INFO 16868 --- [ionShutdownHook] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default' 2022-01-06 23:12:36.031 INFO 16868 --- [ionShutdownHook] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown initiated... 2022-01-06 23:12:36.045 INFO 16868 --- [ionShutdownHook] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown completed. Process finished with exit code -1   제 생각엔 Caused by: org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column "ID"; SQL statement: insert into member (id, name) values (null, ?) [23502-206] 부분이 문제인 것 같은데 강사님 영상의 로그에서는 저렇게 출력되어도 잘 작동되고 id는 잘 생성된다고 하셨습니다. 근데 안되네요 ㅠㅠ 어디가 문제일까요? 코드는 동일합니다. H2도 켜져있고 쿼리문 잘 작동합니다.

인프런 아이디 : IAMSUN 인프런 이메일 : dlatjs4380@gmail.com 깃헙 아이디 :  dlatjs4380@gmail.com 깃헙 Username : KangImseon

#include <bits/stdc++.h> #define endl '\n' using namespace std; vector<int> adjList[10002]; bool visited[10002]; int n, m; int _max = INT_MIN; map<int, int> virus; void fastIO() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); } void DFS(int v, int sum, int com) { _max = max(_max, sum); virus[com] = max(virus[com], sum); for (auto adjV : adjList[v]) { visited[adjV] = 1; DFS(adjV, sum + 1, com); visited[adjV] = 0; } } int main() { fastIO(); //freopen("input.txt", "rt", stdin); cin >> n >> m; for (int i = 0; i < m; i++) { int a, b; cin >> a >> b; adjList[b].push_back(a); } for (int i = 1; i <= 10000; i++) { if (adjList[i].empty()) continue; visited[i] = 1; DFS(i, 1, i); visited[i] = 0; } for (auto e : virus) { if (e.second == _max) { cout << e.first << ' '; } } return EXIT_SUCCESS; } 인접리스트 DFS로 풀었는데 시간 초과가 납니다. 뭐가 문제일까요..?  

안녕하세요  유익한 강의 감사드립니다. 마지막 강의에서 검색된 상품 정보를 무한 스크롤링하는 것까진 정상적으로 동작했는데 for문으로 리스트 정보를 불러오는 부분에서 'WebElement' object is not iterable 타입에러가 발생합니다. 터미널에서는 다음과 같이 에러가 뜹니다. 이럴 경우에 어떻게 해결해야 하나요?    

학습하는 분들께 도움이 되고, 더 좋은 답변을 드릴 수 있도록 질문전에 다음을 꼭 확인해주세요.1. 강의 내용과 관련된 질문을 남겨주세요.2. 인프런의 질문 게시판과 자주 하는 질문(링크)을 먼저 확인해주세요.(자주 하는 질문 링크: https://bit.ly/3fX6ygx)3. 질문 잘하기 메뉴얼(링크)을 먼저 읽어주세요.(질문 잘하기 메뉴얼 링크: https://bit.ly/2UfeqCG)질문 시에는 위 내용은 삭제하고 다음 내용을 남겨주세요.=========================================[질문 템플릿]1. 강의 내용과 관련된 질문인가요? (예/아니오)2. 인프런의 질문 게시판과 자주 하는 질문에 없는 내용인가요? (예/아니오)3. 질문 잘하기 메뉴얼을 읽어보셨나요? (예/아니오)[질문 내용]여기에 질문 내용을 남겨주세요.     안녕하세요. 싱글톤에 관련하여 질문이 있습니다.   1. 싱글톤 컨테이너를 배우면서 '스프링 컨테이너는 싱글톤 패턴을 적용하지 않아도, 객체 인스턴스를 싱글톤으로 관리한다.' 라는 문장이 있는데 스프링 컨테이너가 클래스의 인스턴스가 1개만 생성하도록 보장하는 것(싱글톤 패턴)이 아닌가요? 그렇다면 스프링 컨테이너도 싱글톤 패턴을 적용하고 있는 것이 아닌가요? 저는 스프링 컨테이너가 스프링에서 싱글톤 패턴을 적용해준 것이고, 이를 위한 코드를 직접 짜지 않아도 되기 때문에 자유롭다 + Configuration을 이용하여 DIP, OCP 문제를 해결하였다 라고 이해하였는데, 잘못 이해한 것인가요?   2. 싱글톤 패턴의 문제점에서, private 생성자로 자식 클래스를 만들기 어렵다는 내용이 있는데, constructor가 private이면 자식에게 extends 될 수 없나요?   감사합니다.

안녕하세요 상태값 관련해서 질문이 있습니다. 18:07초에서 step2()가 COMPLETED 되어도 on에는 PASS만 정의되어 있기 때문에 step2의 ExitStatus가 PASS가 아니라면 Job의 BatchStatus와 ExitStatus는 FAILED로 된다고 설명해주셨는데요.  이에 관한 내용은 SimpleJob 부분에서 다뤄주신다고 하셨는데 뒤쪽에 언급이 없으셔서 질문 남기게 되었습니다.  강의 내용처럼 하게 되면 on에 PASS를 넣으면 말씀하신대로 JobExecution이 FAILED가 나옵니다.  설명해주신 맥락대로라면  step2의 on을 FAILED로 두고, step2를 COMPLETED 통과시킨다면 step2에 COMPLETED에 대한 내용은 flow는 정의하지 않았으니 JOB의 BatchStatus와 ExitStatus는 결과적으로는 FAILED가 되어야 하는데 DB를 보면 COMPLETED 상태로 표기되고 있습니다.  즉, 결과는 아래와 같습니다. on에 custom한 ExitStatus(PASS)를 적용하고 step의 ExitStatus를 COMPLETE로 보내면 JOB의 상태는 FAILED로 찍힌다. on에 custom하지 않은 ExitStatus(FAILED)를 적용하고 step의 ExitStatus를 COMPLETED로 보내면 JOB의 상태는 COMPLETED로 찍힌다. 그렇다면 결론적으로 Custom한 ExitStatus값만으로 on에 조건을 걸고 실행시 Step의 ExitStatus가 on조건에 매칭되지 않는다면 Job의 상태는 FAILED이고, 일반적인 ExitStatus값을 on에 조건을 걸고 실행 시 Step의 ExitStatus가 on조건에 매칭되지 않는다면 위의 custom처럼 FAILED가 아니라 해당 Step의 ExitStatus 값으로 Job의 상태가 업데이트 된다.  이렇게 나는데 잘 이해하고 있는게 맞을까요?    @Configuration@RequiredArgsConstructorpublic class TestJobConfiguration { private final JobBuilderFactory jobBuilderFactory; private final StepBuilderFactory stepBuilderFactory; @Bean public Job helloJob() { return jobBuilderFactory.get("job") .start(step1()) .on("COMPLETED") .stop() .from(step1()) .on("*") .to(step2()) .on("FAILED") .stop() .end() .build(); } @Bean public Step step1() { return stepBuilderFactory.get("step1") .tasklet((contribution, chunkContext) -> { System.out.println("step1 completed"); contribution.setExitStatus(ExitStatus.FAILED); return RepeatStatus.FINISHED; }) .build(); } @Bean public Step step2() { return stepBuilderFactory.get("step2") .tasklet((contribution, chunkContext) -> { System.out.println("step2 completed"); return RepeatStatus.FINISHED; }) .build(); }

URL에선 '/save'이고 , viewName은 'save-result' 을 리턴하는데 따로 Post 설정없이 어떻게 가능한가요? 

npm i 로 했는데 저도 똑같이 오류가 나더라구요 그런데 yarn install 로 하자 정상적으로 설치가 되었습니다.   가끔 이런 경우들이 있어서 얼렁뚱땅 해결하고 넘어가곤 했는데, 두 방식 차이로 어떤건 되고 어떤건 안 되는것의 이유가 있을까요?

안녕하세요 제로초님!   socket 연결 관련 부분 진행 중  아래와 같은 에러가 계속 출력되며 서버 동작이 되질 않아 질문 드립니다!   WebSocket connection to 'ws://localhost:3095/socket.io/?EIO=3&transport=websocket' failed: Invalid frame header 우선 제로초님의 백엔드 강의를 먼저 수강하고 제가 코딩한 nestjs 버전의 서버를 사용 중이며, 이 에러로 검색을 해보면 서버와 클라이언트의 버전이 다를 경우 나타날 수 있다고 해서 확인해보니 client는 2.4.0 이고 서버 측은 nestjs/platform-socket.io 8.2.4 버전입니다.코드 상의 문제가 있는지 제로초님의 깃헙 코드와 비교해보고, 제로초님의 서버를 실행해서 테스트 해봤는데요, 우선 제로초님의 express 서버로 실행 시 문제 없이 잘 작동하나, 제로초님의 nestjs 서버를 실행하면 동일 에러 상황이 나오네요 ㅠㅠ 버전은 제로초님 깃헙 코드와 동일하게 설정하여 사용했는데 어떤 문제가 있는지 계속 찾아봐도 잘 모르겠네요..

sudo curl -L "https://github.com/docker/compose/releases/download/1.24.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose   위 버전으로 설치하니까 되네여   문제는 1.28.2 버전의 강의 환경설정과 과연 문제없이 돌아갈지..?;; 

import Vue from 'vue'; console.log(Vue) // ERROR import Vue from 'vue'; 부분에서 다른 행동없이 'vue' 패키지를 잘 가지고 왔는지에 대해 console.log(Vue); 를 찍어보려 했는데 에러코드가 나와서 질문드립니다. 경로가 잘 못 설정된건지 환경변수를 못찾는 것 같은데 스택오버플로우에서는 다른 방향으로 안내하지만 강사님 진행 방식으로 진행이 안되네요, 도움을 주실 수 있을까요? 링크

선생님 안녕하세요~! 이때까지 hover이벤트 적용시 hover하는 요소와 효과적용이 되는 요소가 다를 경우 +, ~같은 선택자를 사용하지 않고 클래스/아이디명/태그명을 바로 이어서 적어서 요소 선택을 하는 것만 했어서 이번 input checked 제어를 하는 부분이 좀 헷갈리는데요,, 혼자서 이래저래 테스트 해보고 얻은 결론인데... 선택자 관련해서 제가 이해한 내용이 맞을까요..?   1. 부모-자식(자손) 관계에서 부모요소를 기준으로 자식요소에 이벤트나 기타 디자인 효과를 줄 때는 ~, +같은 선택자를 사용하지 않고 태그선택자나 클래스 또는 아이디선택자로 바로 이어서 선택한다. 반대로 자식요소를 기준으로 부모요소에는 효과를 적용할 수 없다.   2. 형제선택자, 인접선택자 모두 기준이 되는 요소의 위치가 효과적용이 되는 요소보다 밑에 있을 수는 없다.   기준요소 효과적용요소 => O   효과적용요소 기준요소 => X   결론 : 부모/자식관계든 형제, 인접 관계든 태그 작성 순으로 보았을 때 위에 있는 요소가 아래에 있는 요소를 제어할 순 있지만 아래에 있는 요소가 위에 있는 요소를 제어할 수 없다.

Scanner kb = new Scanner(System.in);String a = kb.next();String b = kb.next();HashMap<Character, Integer> hashMap = new HashMap<>();String result = "YES";for (char i : a.toCharArray()) { hashMap.put(i, hashMap.getOrDefault(i, 0) + 1);}for (char j : b.toCharArray()) { if (!hashMap.containsKey(j) || hashMap.get(j) <= 0) { result = "NO"; } hashMap.put(j,hashMap.get(j)-1);}System.out.println(result); 임포트는 다 잘 되어있는데 채점 결괴에서 두번째 문제만 런타임에러가 나오네요 ㅠㅠ

좀비 프로세스 설명이 피피티와 설명이 조금 다른 것 같은데결국 같은 의미인가요? 피피티에서는 자식은 종료되었지만 부모가 wait하지 않았다는 의미 같아서요

함수 bool 타입을 void로 바꿔도 결과는 동일한데 강의에서는 bool타입으로 하셔서요. 특별한 이유가 있는건가요? 코드 첨부하겠습니다.   #include <iostream> #include <string> using namespace std; class IErrorLog { public: virtual void reportError(const char * errorMessage) = 0; virtual ~IErrorLog() {} }; class FileErrorLog : public IErrorLog { public: void reportError(const char * errorMessage) override { cout << "Writing error to a file" << endl; } }; class ConsolErrorLog : public IErrorLog { public: void reportError(const char * errorMessage) override { cout << "priting error to a Consol" << endl; } }; void doSomething(IErrorLog & log) { log.reportError("Runtime error!!"); } int main() { FileErrorLog file_log; ConsolErrorLog console_log; doSomething(file_log); doSomething(console_log); return 0; }  

ppt 10p, 3번째 동그라미 '따라서 컨볼루션 층의 결과로 출력되는 차원은 [W, H, K]입니다' 문장에서 [W, H, K]가 아니라 [H, W, K] 아닌가요?