How to Handle ConverterNotFoundException in spring Boot JPA Application - spring-boot

Question

I am using JPQL to find the teacher name who teaches Math, But when I
Execute MY JPQL it throw a runtime exception .
ConverterNotFoundException this exception shows me . Here is the
exception details.
org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.lang.String] to type [#org.springframework.data.jpa.repository.Query com.nilmani.jpqlprojectexample.entity.Teacher]
at org.springframework.core.convert.support.GenericConversionService.handleConverterNotFound(GenericConversionService.java:322) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:195) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.core.convert.support.CollectionToCollectionConverter.convert(CollectionToCollectionConverter.java:89) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:41) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:192) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:213) ~[spring-core-5.3.14.jar:5.3.14]
at org.springframework.data.repository.core.support.QueryExecutionResultHandler.postProcessInvocationResult(QueryExecutionResultHandler.java:167) ~[spring-data-commons-2.5.7.jar:2.5.7]
at org.springframework.data.repository.core.support.QueryExecutionResultHandler.postProcessInvocationResult(QueryExecutionResultHandler.java:77) ~[spring-data-commons-2.5.7.jar:2.5.7]
at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:138) ~[spring-data-commons-2.5.7.jar:2.5.7]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.5.7.jar:2.5.7]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.14.jar:5.3.14]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.14.jar:5.3.14]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.14.jar:5.3.14]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-5.3.14.jar:5.3.14]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:145) ~[spring-data-jpa-2.5.7.jar:2.5.7]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.data.repository.core.support.MethodInvocationValidator.invoke(MethodInvocationValidator.java:98) ~[spring-data-commons-2.5.7.jar:2.5.7]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.14.jar:5.3.14]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.14.jar:5.3.14]
at com.sun.proxy.$Proxy88.mathTeacher(Unknown Source) ~[na:na]
at com.nilmani.jpqlprojectexample.controller.TeacherController.getMathTeacher(TeacherController.kt:51) ~[main/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.14.jar:5.3.14]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.14.jar:5.3.14]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.14.jar:5.3.14]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.14.jar:5.3.14]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.14.jar:5.3.14]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1732) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
Here is my function to find the teacher name who teaches Math.
#GetMapping("/exisingMath")
fun getMathTeacher():List<Teacher>{
val existingMath:MutableList<Teacher> = ArrayList(teachRopo.mathTeacher())
existingMath.forEach { e -> println(e) }
return existingMath
}
Define above function in my TeacherController Class
TeacherRepository Class
package com.nilmani.jpqlprojectexample.repository
import com.nilmani.jpqlprojectexample.entity.Teacher
import org.springframework.data.jpa.repository.JpaRepository
import org.springframework.data.jpa.repository.Query
import org.springframework.data.repository.query.Param
interface TeacherRepository : JpaRepository<Teacher,Long> {
#Query("select t.nameOfTeacher from Teacher t where t.subject=1")
fun mathTeacher():List<Teacher>
}
TeacherEntity Class
package com.nilmani.jpqlprojectexample.entity
import com.nilmani.jpqlprojectexample.enum.Subject
import com.nilmani.jpqlprojectexample.enum.University
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.GenerationType
import javax.persistence.Id
#Entity
data class Teacher(
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
val id:Long=-1,
val nameOfTeacher:String="",
val price:Long=-1,
val subject:Int=Subject.MATH.type,
val university:Int=University.OTHER.type
)
I am using IntelliJ IDEA ultimate2021.1 version as code editor,Mac as os

Answer 1

Can you please try if this helps?
change
#Query("select t.nameOfTeacher from Teacher t where t.subject=1")
Into:
#Query("select t from Teacher t where t.subject=1")