Exception in thread "main" org.hibernate.MappingException: Cannot use identity column key generation with mapping for:

Exception in thread "main" org.hibernate.MappingException: Cannot use identity column key generation with <union-subclass> mapping for: com.varasofttech.pojo.table_per_concrete_class.PermanentEmployee

    at org.hibernate.persister.entity.UnionSubclassEntityPersister.<init>(UnionSubclassEntityPersister.java:96)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:163)
    at org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:135)
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:401)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1859)
    at com.varasofttech.util.HibernateUtil.buildSessionFactory(HibernateUtil.java:36)
    at com.varasofttech.util.HibernateUtil.getSessionFacoty(HibernateUtil.java:22)
    at com.varasofttech.client.Application.main(Application.java:22)

Entity:

@Entity
@Table(name="Persons")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Person implements Serializable {    
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long id;
    // some other properties
}

Problem:
Hibernate does not support the use of identity or increment generation strategy for "table per concrete class with union strategy".

@Entity
@Table(name="Persons")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Person implements Serializable {
    
    @Id
    @GeneratedValue(strategy=GenerationType.TABLE)
    private long id;
    // some other properties

}

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org.hibernate.MappingException: Unknown entity

Problem:
This exception will occur mainly because of the following two reasons

1. Making the @Entity with the wrong annotation

import org.hibernate.annotations.Entity; 
@Entity
public class Employee implements Serializable {
    ...
}

solution for this one is changing the package name.

import javax.persistence.Entity;

2. Missing the @Entity annotation

public class Employee implements Serializable {
    ...
}

solution for this one is adding the @Entity annotation to the class.

import javax.persistence.Entity;

@Entity
public class Employee implements Serializable {

}

Happy Coding!!!

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The method getDispatcherType() is undefined for the type HttpServletRequest

An error occurred at line: [42] in the generated java file: [D:\Upgrade\Upgrade_Eclipse_Worlspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\Spring4Hiberante4Integration\org\apache\jsp\WEB_002dINF\pages\employeeList_jsp.java]

The method getDispatcherType() is undefined for the type HttpServletRequest

Solution:

<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>3.1.0</version>
</dependency>

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No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode \-[IDENT] IdentNode: 'e' {originalText=e}

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode 
 \-[IDENT] IdentNode: 'e' {originalText=e}

HQL query:
Query query = session.createQuery("SELECT e FROM Employee");

Problem: 
In the above query, 'e' alias name is given in Employee table.

Solution: 
Query query = session.createQuery("SELECT e FROM Employee e");

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Caused by: java.lang.ClassNotFoundException: javax.servlet.SessionCookieConfig

Exception:

Caused by: java.lang.ClassNotFoundException: javax.servlet.SessionCookieConfig
        at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 38 more

Solution: We need to migrate Servlet version 2.5 to 3.0.1

The final dependency was

<dependency>
     <groupId>javax.servlet</groupId>
     <artifactId>javax.servlet-api</artifactId>
     <version>3.0.1</version>
</dependency>

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Exception in thread "main" org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

Exception in thread "main" org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
    at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:104)
    at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:71)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:209)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:111)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:234)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:206)
    at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1885)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1843)
    at com.ranga.MultiTenancyDemo.main(MultiTenancyDemo.java:34)
 

Problem:

// Create the SessionFactory from hibernate.cfg.xml
        Configuration configuration = new Configuration();
       
         System.out.println("Hibernate Configuration loaded.");
       
        //apply configuration property settings to StandardServiceRegistryBuilder
        serviceRegistry = new StandardServiceRegistryBuilder().applySettings(
                configuration.getProperties()).build();
        System.out.println("Hibernate serviceRegistry created.");
       
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        System.out.println("Hibernate sessionFactory object created.");    

Solution:

After creation of Configuration object, we need to call the         configuration.configure("hibernate.cfg.xml"); method.

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Exception in thread "main" org.hibernate.HibernateException: persist is not valid without active transaction

Problem:  The problem in Configuration file.

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">       
        <property name="dataSource" ref="dataSource"></property>       
        <!-- Configuring the  Hibernate properties -->
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">${hibernate.dialect}</prop>
                <prop key="hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
                <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>               
                <prop key="hibernate.current_session_context_class">${hibernate.current_session_context_class}</prop>
            </props>       
        </property>
        <property name="annotatedClasses">
            <list>
                <value>com.ranga.Employee</value>
            </list>
        </property>       
    </bean>

------------------------------------------------------------------------------------------------------------------------------

hibernate.current_session_context_class is required only for JTA transactions.

Solution: Remove the hibernate.current_session_context_class property in sessionFactory. Now the code looks like

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">       
        <property name="dataSource" ref="dataSource"></property>       
        <!-- Configuring the  Hibernate properties -->
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">${hibernate.dialect}</prop>
                <prop key="hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
                <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>               
            </props>       
        </property>
        <property name="annotatedClasses">
            <list>
                <value>com.ranga.Employee</value>
            </list>
        </property>       
    </bean>

Click here to see more information.

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java.lang.NoClassDefFoundError: org/aopalliance/intercept/MethodInterceptor

Problem:

While doing transactions management with the annotations, prior to Spring 3.0 we are adding aopalliance.jar file. In latest Spring bundle this jar file not available. If we add below line applicationContext.xml we need to add the aopalliance.jar file other wise it will throws the java.lang.NoClassDefFoundError: org/aopalliance/intercept/MethodInterceptor

<tx:annotation-driven transaction-manager="hibernateTransactionManager"/>

Solution: Add the aopalliance.jar file to classpath or pom.xml file.

Click here to Download

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java.lang.NoClassDefFoundError: org/springframework/dao/DataAccessException

Problem: The problem is we are missing to add the Spring Transaction jar file to class path.

Solution: Add the spring-tx- x.x.RELEASE.jar to the class path. here x.x is spring current version you are using.

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Caused by: java.sql.SQLSyntaxErrorException: ORA-00918: column ambiguously defined

Caused by: java.sql.SQLSyntaxErrorException: ORA-00918: column ambiguously defined

Problem: The problem comes from while triggering a select query. In select query the multiple tables having the same column name but if we specified with out any prefix then it will throws the column ambiguously defined.

Example: Assume it two table Student and Employee. Both tables is having id, id.

Then while fetching the recored

Select id, * from Student s, Employee e;

Solution: Add prefix to the column

Select s.id, e.id, * from Student s, Employee e;

Note: Columns must be referenced as TABLE.COLUMN or TABLE_ALIAS.COLUM .

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org.apache.ibatis.exceptions.TooManyResultsException:

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 2

Example is : while fetching by name, name founds in two times.

ID          NAME                           DESCRIPTION

1            Test                              Test Desc...

2            Test                              Test Desc1...

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