Why JPA Hibernate changes the name of the field? - mysql

Question

In model class I have isActive field with is boolean, that represent the is_active field in MySql DB. Here is whole model class:
package ca.gatin.model;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
#Entity
#Table(name = "Account")
public class Account {
#Id
#GeneratedValue
private Long id;
#Column(name = "first_name")
private String firstName;
#Column(name = "last_name")
private String lastName;
#Column(nullable = false, unique = true)
private String email;
#Column(nullable = false)
private String password;
#Column(name = "is_active", nullable = false)
private boolean isActive;
#Column(name = "date_created")
private Date dateCreated;
#Column(name = "date_last_modified")
private Date dateLastModified;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean isActive() {
return isActive;
}
public void setActive(boolean isActive) {
this.isActive = isActive;
}
public Date getDateCreated() {
return dateCreated;
}
public void setDateCreated(Date dateCreated) {
this.dateCreated = dateCreated;
}
public Date getDateLastModified() {
return dateLastModified;
}
public void setDateLastModified(Date dateLastModified) {
this.dateLastModified = dateLastModified;
}
}
But when I fetch account let's say through REST API like:
#RequestMapping(
value = "/{id}",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
public ServiceResponse<Account> getAll(#PathVariable("id") Long id) {
ServiceResponse<Account> serviceResponse = accountService.getAccountById(id);
return serviceResponse;
}
In a reply object I get isActive field renamed by Hibernate to "active" like this:
{
"id": 19,
"firstName": "Julia",
"lastName": "Sarandi",
"email": "julia#gatin.ca",
"password": "111111",
"dateCreated": 1451293826000,
"dateLastModified": null,
"active": true
}
Why? Why all other field's names stay same as in Account class, but isActive is renamed?
That is one question, and another question is:
I am new in Hibernate, and I do no understand why in logs of Hibernate DB requests is shows some weird queries:
Hibernate: select account0_.id as id1_0_0_, account0_.date_created as date_cre2_0_0_, account0_.date_last_modified as date_las3_0_0_, account0_.email as email4_0_0_, account0_.first_name as first_na5_0_0_, account0_.is_active as is_activ6_0_0_, account0_.last_name as last_nam7_0_0_, account0_.password as password8_0_0_ from Account account0_ where account0_.id=?
What query language is it? What are symbols: "0_", "0_0_". Can I switch logs to show MySQL queries to make it more understandable?
FYI
In my application.properties file I have following configuration:
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.DefaultNamingStrategy

Answer 1

Change getter and setter method name for isActive field as:
public boolean getIsActive() {
return isActive;
}
public void setIsActive(boolean isActive) {
this.isActive = isActive;
}
Then it return isActive in response.

Answer 2

That has nothing to do with Hibernate, and everything to do with your JSON marshaller. Spring uses Jackson, and Jackson uses bean properties (i.e. getters) to access the data and transform them to JSON fields. Your getter is named isActive(), and thus corresponds to a bean property named active, hence the name of the attribute in the JSON.
If you want the JSON field to be named isActive, then your getter should be isIsActive(). Or much better, you should annotate it with #JsonProperty("isActive").
To answer your second question, the query is a SQL query, generated by Hibernate. It changes the name of tables and assigns aliases to columns mainly to disambiguate tables, and fields of different tables that could have the same name, AFAIK.