Spring Hibernate not to fetch the child data always

Question

I have two tables Devices and Rules, a device can have n number of rules so they exist in One to Many Associations and vice versa.

I am using Spring+Hibernate+REST , i never want to fetch the Rules data when i fetch Devices Data, when i use lazy fetch , i am getting lazy initialization exception. I am having hibernate mapping via annotations. kindly suggest some way where i can skip the retrieval of Rules data while retrieving the devices data.

Find my classes below:

@Entity
@Table(name="device")
@DynamicUpdate
@SelectBeforeUpdate
public class Devices implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @Column(name="DEVICE_ID")
    private Integer deviceId;

    @Column(name="DEVICE_DESC")
    private String deviceDesc;

    @Column(name="DEVICE_NAME")
    private String deviceName;


    @OneToMany(mappedBy="device",fetch = FetchType.LAZY)
    @JsonIgnore
    private List<Rules> rules;



    public Devices() {
    }

    public Integer getDeviceId() {
        return this.deviceId;
    }

    public void setDeviceId(Integer deviceId) {
        this.deviceId = deviceId;
    }


    public List<Rules> getRules() {
        return this.rules;
    }

    public void setRules(List<Rules> rules) {
        this.rules = rules;
    }



}

public class Rules implements Serializable {
    @Id
    @Column(name="RULE_ID")
    private Integer id;

    public Integer getId() {
        return this.id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @ManyToOne
    @JoinColumn(name="DEV_ID")
    @JsonIgnore
    private Devices device;

    // getter and setter for device follows
}

Find the exception below :

SEVERE: Servlet.service() for servlet [mvc-dispatcher] in context with path [/MyWork] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.beans.Devices.rules, no session or session was closed] with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.beans.Devices.rules, no session or session was closed
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:393)
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:385)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:378)
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:112)
    at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:266)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:95)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:99)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:219)
    at com.google.gson.internal.bind.ObjectTypeAdapter.write(ObjectTypeAdapter.java:107)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:99)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:219)
    at com.google.gson.Gson.toJson(Gson.java:600)
    at com.google.gson.Gson.toJson(Gson.java:579)
    at org.springframework.http.converter.json.GsonHttpMessageConverter.writeInternal(GsonHttpMessageConverter.java:199)
    at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:100)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:222)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:153)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:165)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:80)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:409)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1044)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

You can unproxy the object before serializing http://stackoverflow.com/questions/11228838/how-to-unproxy-a-hibernate-object Just exclude the Hibernate.initialize(entity); line to avoid collection init — StanislavL, Aug 26 '16 at 11:06
@StanislavL Could you please let me know where the unproxy method has to be called or is it a overridden method? I am asking this becoz i am using Spring+hibernate — user1058913, Aug 26 '16 at 11:12
Check http://stackoverflow.com/questions/11746499/solve-failed-to-lazily-initialize-a-collection-of-role-exception — Justinas Jakavonis, Aug 26 '16 at 11:13

score 0 · Answer 1 · answered Aug 26 '16 at 12:05

0

You are reading Devices within a transaction, at this point Rules is proxied. Read here.

When you try to device.getRules() (at com.google.gson.Gson.toJson(Gson.java:579) in your stack trace) the transaction is already finished and Rule is still not fetched and can no longer be fetched.

You need to make sure you initialise rules before transaction is finished or make it eagerly loaded.

Spring Hibernate not to fetch the child data always

1 Answers1