Getting Mockito can only mock non-private & non-final classes error while running test cases - spring

Question

I'm using Java 11. Tried almost everything, still it's not working. Done Invalidate Cache & restart as well.
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This is the dependencies, I've added in pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>*emphasized text*
This is the class which is mocking and it's not able to mock, I've some test cases for the UserService.
This is UserServiceImpltest.java
package com.stackroute.keepnote.test.service;
import static org.junit.Assert.*;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.when;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Optional;
import com.stackroute.keepnote.exceptions.UserNotFoundException;
import com.stackroute.keepnote.service.UserServiceImpl;
import org.junit.Before;
import org.junit.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import com.stackroute.keepnote.exceptions.UserAlreadyExistsException;
import com.stackroute.keepnote.model.User;
import com.stackroute.keepnote.repository.UserRepository;
public class UserServiceImplTest {
#Mock
UserRepository userRepository;
User user;
#InjectMocks
UserServiceImpl userService;
List<User> userList = null;
Optional<User> options;
#Before
public void setUp() {
MockitoAnnotations.initMocks(this);
user = new User();
user.setUserAddedDate(new Date());
user.setUserId("John123");
user.setUserMobile("1234567789");
user.setUserName("john");
user.setUserPassword("johnpass");
userList = new ArrayList<>();
userList.add(user);
options = Optional.of(user);
}
This is the User class, which is declare public
#Document
public class User {
/*
* This class should have five fields (userId,userName,
* userPassword,userMobile,userAddedDate). Out of these five fields, the field
* userId should be annotated with #Id (This annotation explicitly specifies the document
* identifier). This class should also contain the getters and setters for the
* fields, along with the no-arg , parameterized constructor and toString
* method.The value of userAddedDate should not be accepted from the user but
* should be always initialized with the system date.
*/
#Id
private String userId;
private String userName;
private String userPassword;
private String userMobile;
private Date userAddedDate;
public User() {
}
public User(String userId, String userName, String userPassword, String userMobile, Date userAddedDate) {
this.userId = userId;
this.userName = userName;
this.userPassword = userPassword;
this.userMobile = userMobile;
this.userAddedDate = userAddedDate;
}
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserPassword() {
return userPassword;
}
public void setUserPassword(String userPassword) {
this.userPassword = userPassword;
}
public String getUserMobile() {
return userMobile;
}
public void setUserMobile(String userMobile) {
this.userMobile = userMobile;
}
public void setUserAddedDate(Date userAddedDate) {
this.userAddedDate = userAddedDate;
}

Answer 1

Based on your "Failed to release mocks" comment, my guess is that you have an older version of the spring-boot-starter-test dependency. If you're not able to update your spring boot version, you can update mockito and byte-buddy, either in <dependencies> or <dependencyManagement>:
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>3.6.28</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>1.10.19</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy-agent</artifactId>
<version>1.10.19</version>
<scope>test</scope>
</dependency>
I started seeing that "Failed to release mocks" error when I upgraded to Java SE 15:
org.mockito.exceptions.base.MockitoException:
Failed to release mocks
This should not happen unless you are using a third-part mock maker
At the bottom of the stack trace, here's the clue that it's an outdated byte-buddy problem:
Caused by: java.lang.IllegalArgumentException: Unknown Java version: 15
at net.bytebuddy.ClassFileVersion.ofJavaVersion(ClassFileVersion.java:232)
at net.bytebuddy.ClassFileVersion$VersionLocator$ForJava9CapableVm.locate(ClassFileVersion.java:485)
The version of spring-boot-starter-test that I am using has outdated mockito and byte-buddy dependencies that aren't aware of the more recent Java releases. Updating the dependencies should clear up your problem.

Answer 2

If you are using Spring boot, you need to remove all other dependencies (mockito, asm, jaxb-api). This starter spring-boot-starter-test make sure everything you need for your test are already there with the correct version. You can check the pom here.