Cassandra Exception : @Table annotation not found on the class

Question

I am new to cassandra database. I am trying to map a table to a java class.

My java class:

@Table("user")
public class User implements Serializable 
{   
    @PrimaryKey
    @Column(value = "id")
    private int id;
    @Column(value = "first_name")
    private String firstName;

    //setters and getters
}

Dao class:

 public class UserDaoImpl {

        Cluster cluster = Cluster.builder().addContactPoint("127.0.0.1").build();
        Session session = cluster.connect("agtr_api");
        MappingManager manager = new MappingManager(session);
        Mapper<User> mapper = manager.mapper(User.class);
        public User getUserById(int id){    
             User u = mapper.get(id);
             return u;
        }     
    }

When i run my application on server, It throws following exception:

SEVERE: Servlet.service() for servlet [spring] in context with path [/aggregator-api] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: @Table annotation was not found on class com.data.User] with root cause java.lang.IllegalArgumentException: @Table annotation was not found on class com.data.User at com.datastax.driver.mapping.AnnotationChecks.getTypeAnnotation(AnnotationChecks.java:43) at com.datastax.driver.mapping.AnnotationParser.parseEntity(AnnotationParser.java:76) at com.datastax.driver.mapping.MappingManager.getMapper(MappingManager.java:226) at com.datastax.driver.mapping.MappingManager.mapper(MappingManager.java:182) at com.etl.aapi.common.dao.UserDaoImpl.(UserDaoImpl.java:19) at com.etl.aapi.common.controller.UserController.a(UserController.java:13) 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.springframework. web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:832) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:743) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:961) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895) at org.springframework.web.servlet.FrameworkServlet.processRequest(Fra meworkServlet.java:967) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) at javax.servlet.http.HttpServlet.service(HttpServlet.java:624) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.Aut henticatorBase.invoke(AuthenticatorBase.java:505) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:958) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:452) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1087) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thre ad.run(Thread.java:745)

Answer 1

You can declare also you keyspace name. Try to use the complete syntax as below:

@Table(keyspace = "yourKeyspace", name = "yourTable")

Answer 2

The "@Annotation" error is misleading as you rightly guess and the exception does not directly tell what is the actual error. The underlying problem would always be in your Domain/Model class fields/columns definition such as column name missing, miss match etc, always watch out your Domain/Model class.

Besides, If you use Achilles library and @Table annotation from Achilles, you will not get correct error. As a workaround you can additionally use @Table annotation from DataStax driver which will try to throw you more details in the exception stack trace.