Error creating spring boot bean - "The blank final field em may not have been initialized" - spring

Question

I am a newbie for the spring boot framework. I have successfully done crud operation. After that I have decided that to do Advanced search concepts. Please see the code below, which I used.
package com.lean.repository;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import javax.persistence.EntityManager;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import org.springframework.data.jpa.repository.JpaRepository;
import com.lean.entity.Merchant;
public interface MerchantDao extends JpaRepository<Merchant, Long> {
EntityManager em;
public List<Merchant> findAllByNameIn(Set<String> name);
public default List<Merchant> findMerchantList(String name, String email) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Merchant> cq = cb.createQuery(Merchant.class);
Root<Merchant> book = cq.from(Merchant.class);
List<Predicate> predicates = new ArrayList<>();
if (name != null) {
predicates.add(cb.equal(book.get("name"), name));
}
if (email != null) {
predicates.add(cb.equal(book.get("email"), email));
}
cq.where(predicates.toArray(new Predicate[0]));
return em.createQuery(cq).getResultList();
};
}
Here, I am getting the below error.
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'merchantDao': Invocation of init method failed; nested exception is java.lang.Error: Unresolved compilation problem:
The blank final field em may not have been initialized
When I am trying to get the"EntityManager em" entity object, I will get the above error.
Please help someone to fix the issue. Thanks in advance

Answer 1

Try this :-
#PersistenceContext
private EntityManager em;
Also check for below dependencies
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.11.Final</version>
</dependency>
</dependencies>