diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/IUserDAO.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/IUserDAO.java
new file mode 100644
index 0000000000..41a3716ec7
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/IUserDAO.java
@@ -0,0 +1,12 @@
+package org.baeldung.persistence.dao;
+
+import java.util.List;
+import java.util.Map;
+
+import org.baeldung.persistence.model.User;
+
+public interface IUserDAO {
+    List<User> searchUser(Map<String, Object> params);
+
+    void save(User entity);
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserDAO.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserDAO.java
new file mode 100644
index 0000000000..c3f6107d05
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserDAO.java
@@ -0,0 +1,49 @@
+package org.baeldung.persistence.dao;
+
+import java.util.List;
+import java.util.Map;
+
+import javax.persistence.EntityManager;
+import javax.persistence.PersistenceContext;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+
+import org.baeldung.persistence.model.User;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public class UserDAO implements IUserDAO {
+
+    @PersistenceContext
+    private EntityManager entityManager;
+
+    @Override
+    public List<User> searchUser(final Map<String, Object> params) {
+        final CriteriaBuilder builder = entityManager.getCriteriaBuilder();
+        final CriteriaQuery<User> query = builder.createQuery(User.class);
+        final Root r = query.from(User.class);
+
+        Predicate predicate = builder.conjunction();
+
+        for (final Map.Entry<String, Object> param: params.entrySet()){
+            if (param.getKey().equalsIgnoreCase("age")) {
+                predicate = builder.and(predicate, builder.greaterThanOrEqualTo(r.get(param.getKey()), Integer.parseInt(param.getValue().toString())));
+            }
+            else{
+                predicate = builder.and(predicate, builder.like(r.get(param.getKey()), "%" + param.getValue() + "%"));
+            }
+        }
+        query.where(predicate);
+
+        final List<User> result = entityManager.createQuery(query).getResultList();
+        return result;
+    }
+
+    @Override
+    public void save(final User entity) {
+        entityManager.persist(entity);
+    }
+
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserRepository.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserRepository.java
new file mode 100644
index 0000000000..de7acf60d5
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserRepository.java
@@ -0,0 +1,9 @@
+package org.baeldung.persistence.dao;
+
+import org.baeldung.persistence.model.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
+
+public interface UserRepository extends JpaRepository<User, Long>, JpaSpecificationExecutor<User> {
+
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecifications.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecifications.java
new file mode 100644
index 0000000000..a0f545b158
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecifications.java
@@ -0,0 +1,45 @@
+package org.baeldung.persistence.dao;
+
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+
+import org.baeldung.persistence.model.User;
+import org.baeldung.persistence.model.User_;
+import org.springframework.data.jpa.domain.Specification;
+
+public class UserSpecifications {
+    public static Specification<User> firstNameIsLike(final String term) {
+
+        return new Specification<User>() {
+            @Override
+            public Predicate toPredicate(final Root<User> root, final CriteriaQuery<?> query, final CriteriaBuilder cb) {
+                return cb.like(root.get(User_.firstName), "%"+term+"%");
+            }
+
+        };
+    }
+
+    public static Specification<User> lastNameIsLike(final String term) {
+
+        return new Specification<User>() {
+            @Override
+            public Predicate toPredicate(final Root<User> root, final CriteriaQuery<?> query, final CriteriaBuilder cb) {
+                return cb.like(root.get(User_.lastName), "%" + term + "%");
+            }
+
+        };
+    }
+
+    public static Specification<User> ageIsGreaterThan(final int minAge) {
+
+        return new Specification<User>() {
+            @Override
+            public Predicate toPredicate(final Root<User> root, final CriteriaQuery<?> query, final CriteriaBuilder cb) {
+                return cb.greaterThanOrEqualTo(root.get(User_.age), minAge);
+            }
+
+        };
+    }
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecificationsBuilder.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecificationsBuilder.java
new file mode 100644
index 0000000000..dd7b6727ec
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/dao/UserSpecificationsBuilder.java
@@ -0,0 +1,46 @@
+package org.baeldung.persistence.dao;
+
+import static org.baeldung.persistence.dao.UserSpecifications.ageIsGreaterThan;
+import static org.baeldung.persistence.dao.UserSpecifications.firstNameIsLike;
+import static org.baeldung.persistence.dao.UserSpecifications.lastNameIsLike;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import org.baeldung.persistence.model.User;
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.data.jpa.domain.Specifications;
+
+public class UserSpecificationsBuilder {
+
+    public static Specification<User> buildUserSpecs(final Map<String, Object> params) {
+        if (params.size() == 0)
+            return null;
+
+        final List<Specification<User>> specs = new ArrayList<Specification<User>>();
+        String key, value;
+
+        for (final Map.Entry<String, Object> param : params.entrySet()) {
+            key = param.getKey();
+            value = param.getValue().toString();
+            if (key.equalsIgnoreCase("age")) {
+                specs.add(ageIsGreaterThan(Integer.parseInt(value)));
+            } else if (key.equalsIgnoreCase("firstName")) {
+                specs.add(firstNameIsLike(value));
+            } else if (key.equalsIgnoreCase("lastName")) {
+                specs.add(lastNameIsLike(value));
+            }
+        }
+
+        if (specs.size() == 0)
+            return null;
+
+        Specification<User> result = specs.get(0);
+        for (int i = 1; i < specs.size(); i++) {
+            result = Specifications.where(result).and(specs.get(i));
+        }
+        return result;
+
+    }
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User.java
new file mode 100644
index 0000000000..d220f4458e
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User.java
@@ -0,0 +1,96 @@
+package org.baeldung.persistence.model;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+
+    private String firstName;
+
+    private String lastName;
+
+    private String email;
+
+    private int age;
+
+    public User() {
+        super();
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(final Long id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(final String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(final String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(final String username) {
+        email = username;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(final int age) {
+        this.age = age;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((email == null) ? 0 : email.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        final User user = (User) obj;
+        if (!email.equals(user.email))
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder builder = new StringBuilder();
+        builder.append("User [firstName=").append(firstName).append("]").append("[lastName=").append(lastName).append("]").append("[username").append(email).append("]");
+        return builder.toString();
+    }
+
+}
\ No newline at end of file
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User_.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User_.java
new file mode 100644
index 0000000000..c7b6ba2de8
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/model/User_.java
@@ -0,0 +1,11 @@
+package org.baeldung.persistence.model;
+
+import javax.persistence.metamodel.SingularAttribute;
+import javax.persistence.metamodel.StaticMetamodel;
+
+@StaticMetamodel(User.class)
+public class User_ {
+    public static volatile SingularAttribute<User, String> firstName;
+    public static volatile SingularAttribute<User, String> lastName;
+    public static volatile SingularAttribute<User, Integer> age;
+}
\ No newline at end of file
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/persistence/service/impl/UserService.java b/spring-security-rest-full/src/main/java/org/baeldung/persistence/service/impl/UserService.java
new file mode 100644
index 0000000000..accf20ca5e
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/persistence/service/impl/UserService.java
@@ -0,0 +1,42 @@
+package org.baeldung.persistence.service.impl;
+
+import java.util.List;
+import java.util.Map;
+
+import org.baeldung.persistence.dao.IUserDAO;
+import org.baeldung.persistence.dao.UserRepository;
+import org.baeldung.persistence.dao.UserSpecificationsBuilder;
+import org.baeldung.persistence.model.User;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class UserService {
+    @Autowired
+    private IUserDAO dao;
+
+    @Autowired
+    private UserRepository repository;
+
+    public UserService() {
+        super();
+    }
+
+    public void saveUser(final User user) {
+        dao.save(user);
+    }
+
+    public List<User> searchUser(final Map<String, Object> params) {
+        return dao.searchUser(params);
+    }
+
+    public List<User> searchBySpecification(final Map<String, Object> params) {
+        final Specification<User> spec = UserSpecificationsBuilder.buildUserSpecs(params);
+        if (spec == null)
+            return repository.findAll();
+        return repository.findAll(spec);
+    }
+}
diff --git a/spring-security-rest-full/src/main/java/org/baeldung/web/controller/UserController.java b/spring-security-rest-full/src/main/java/org/baeldung/web/controller/UserController.java
new file mode 100644
index 0000000000..be1bc25b76
--- /dev/null
+++ b/spring-security-rest-full/src/main/java/org/baeldung/web/controller/UserController.java
@@ -0,0 +1,69 @@
+package org.baeldung.web.controller;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.baeldung.persistence.model.User;
+import org.baeldung.persistence.service.impl.UserService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class UserController {
+
+    @Autowired
+    private UserService service;
+
+    public UserController() {
+        super();
+    }
+
+    @RequestMapping(method = RequestMethod.GET, value = "/users")
+    @ResponseBody
+    public List<User> findAll(@RequestParam(value = "search", required = false) final String search) {
+        final Map<String, Object> params = new HashMap<String, Object>();
+
+        if (search != null) {
+            final Pattern pattern = Pattern.compile("(\\w+?):(\\w+?),");
+            final Matcher matcher = pattern.matcher(search + ",");
+            while (matcher.find()) {
+                params.put(matcher.group(1), matcher.group(2));
+            }
+        }
+        return service.searchUser(params);
+    }
+
+    @RequestMapping(method = RequestMethod.GET, value = "/users/spec")
+    @ResponseBody
+    public List<User> findAllBySpecification(@RequestParam(value = "search", required = false) final String search) {
+        final Map<String, Object> params = new HashMap<String, Object>();
+
+        if (search != null) {
+            final Pattern pattern = Pattern.compile("(\\w+?):(\\w+?),");
+            final Matcher matcher = pattern.matcher(search + ",");
+            while (matcher.find()) {
+                params.put(matcher.group(1), matcher.group(2));
+            }
+        }
+        return service.searchBySpecification(params);
+    }
+
+    @RequestMapping(method = RequestMethod.GET, value = "/users/new")
+    @ResponseBody
+    public long addUser(@RequestParam("first") final String first, @RequestParam("last") final String last, @RequestParam("age") final int age) {
+        final User user = new User();
+        user.setFirstName(first);
+        user.setLastName(last);
+        user.setEmail("john@doe.com");
+        user.setAge(age);
+        service.saveUser(user);
+        return user.getId();
+    }
+}
diff --git a/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPACriteriaQueryTest.java b/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPACriteriaQueryTest.java
new file mode 100644
index 0000000000..aec73e5f5f
--- /dev/null
+++ b/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPACriteriaQueryTest.java
@@ -0,0 +1,105 @@
+package org.baeldung.persistence.query;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.baeldung.persistence.model.User;
+import org.baeldung.persistence.service.impl.UserService;
+import org.baeldung.spring.PersistenceConfig;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+import org.springframework.test.context.transaction.TransactionConfiguration;
+import org.springframework.transaction.annotation.Transactional;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { PersistenceConfig.class }, loader = AnnotationConfigContextLoader.class)
+@Transactional
+@TransactionConfiguration
+public class JPACriteriaQueryTest {
+
+    @Autowired
+    private UserService userService;
+
+    private User userJohn;
+
+    private User userTom;
+
+    @Before
+    public void init() {
+        userJohn = new User();
+        userJohn.setFirstName("John");
+        userJohn.setLastName("Doe");
+        userJohn.setEmail("john@doe.com");
+        userJohn.setAge(22);
+        userService.saveUser(userJohn);
+
+        userTom = new User();
+        userTom.setFirstName("Tom");
+        userTom.setLastName("Doe");
+        userTom.setEmail("tom@doe.com");
+        userTom.setAge(26);
+        userService.saveUser(userTom);
+    }
+
+    @Test
+    public void givenFirstAndLastName_whenGettingListOfUsers_thenCorrect() {
+        final Map<String, Object> params = new HashMap<String, Object>();
+        params.put("firstName", "John");
+        params.put("lastName", "Doe");
+
+        final List<User> result = userService.searchUser(params);
+
+        assertEquals(1, result.size());
+        assertEquals(userJohn.getEmail(), result.get(0).getEmail());
+    }
+
+    @Test
+    public void givenLast_whenGettingListOfUsers_thenCorrect() {
+        final Map<String, Object> params = new HashMap<String, Object>();
+        params.put("lastName", "doe");
+
+        final List<User> result = userService.searchUser(params);
+        assertEquals(2, result.size());
+    }
+
+    @Test
+    public void givenLastAndAge_whenGettingListOfUsers_thenCorrect() {
+        final Map<String, Object> params = new HashMap<String, Object>();
+        params.put("lastName", "doe");
+        params.put("age", "25");
+
+        final List<User> result = userService.searchUser(params);
+
+        assertEquals(1, result.size());
+        assertEquals(userTom.getEmail(), result.get(0).getEmail());
+    }
+
+    @Test
+    public void givenWrongFirstAndLast_whenGettingListOfUsers_thenCorrect() {
+        final Map<String, Object> params = new HashMap<String, Object>();
+        params.put("firstName", "Adam");
+        params.put("lastName", "Fox");
+
+        final List<User> result = userService.searchUser(params);
+        assertEquals(0, result.size());
+    }
+
+    @Test
+    public void givenPartialFirst_whenGettingListOfUsers_thenCorrect() {
+        final Map<String, Object> params = new HashMap<String, Object>();
+        params.put("firstName", "jo");
+
+        final List<User> result = userService.searchUser(params);
+
+        assertEquals(1, result.size());
+        assertEquals(userJohn.getEmail(), result.get(0).getEmail());
+    }
+}
diff --git a/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPASpecificationsTest.java b/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPASpecificationsTest.java
new file mode 100644
index 0000000000..9a942780cf
--- /dev/null
+++ b/spring-security-rest-full/src/test/java/org/baeldung/persistence/query/JPASpecificationsTest.java
@@ -0,0 +1,89 @@
+package org.baeldung.persistence.query;
+
+import static org.baeldung.persistence.dao.UserSpecifications.ageIsGreaterThan;
+import static org.baeldung.persistence.dao.UserSpecifications.firstNameIsLike;
+import static org.baeldung.persistence.dao.UserSpecifications.lastNameIsLike;
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.baeldung.persistence.dao.UserRepository;
+import org.baeldung.persistence.model.User;
+import org.baeldung.spring.PersistenceConfig;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.jpa.domain.Specifications;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+import org.springframework.test.context.transaction.TransactionConfiguration;
+import org.springframework.transaction.annotation.Transactional;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { PersistenceConfig.class }, loader = AnnotationConfigContextLoader.class)
+@Transactional
+@TransactionConfiguration
+public class JPASpecificationsTest {
+
+    @Autowired
+    private UserRepository repository;
+
+    private User userJohn;
+
+    private User userTom;
+
+    @Before
+    public void init() {
+        userJohn = new User();
+        userJohn.setFirstName("John");
+        userJohn.setLastName("Doe");
+        userJohn.setEmail("john@doe.com");
+        userJohn.setAge(22);
+        repository.save(userJohn);
+
+        userTom = new User();
+        userTom.setFirstName("Tom");
+        userTom.setLastName("Doe");
+        userTom.setEmail("tom@doe.com");
+        userTom.setAge(26);
+        repository.save(userTom);
+    }
+
+    @Test
+    public void givenLast_whenGettingListOfUsers_thenCorrect() {
+        final List<User> result = repository.findAll(lastNameIsLike("doe"));
+        assertEquals(2, result.size());
+    }
+
+    @Test
+    public void givenFirstAndLastName_whenGettingListOfUsers_thenCorrect() {
+        final List<User> result = repository.findAll(Specifications.where(lastNameIsLike("doe")).and(firstNameIsLike("john")));
+
+        assertEquals(1, result.size());
+        assertEquals(userJohn.getEmail(), result.get(0).getEmail());
+    }
+
+    @Test
+    public void givenLastAndAge_whenGettingListOfUsers_thenCorrect() {
+        final List<User> result = repository.findAll(Specifications.where(lastNameIsLike("doe")).and(ageIsGreaterThan(25)));
+
+        assertEquals(1, result.size());
+        assertEquals(userTom.getEmail(), result.get(0).getEmail());
+    }
+
+    @Test
+    public void givenWrongFirstAndLast_whenGettingListOfUsers_thenCorrect() {
+        final List<User> result = repository.findAll(Specifications.where(lastNameIsLike("Adam")).and(firstNameIsLike("Fox")));
+        assertEquals(0, result.size());
+    }
+
+    @Test
+    public void givenPartialFirst_whenGettingListOfUsers_thenCorrect() {
+        final List<User> result = repository.findAll(firstNameIsLike("jo"));
+
+        assertEquals(1, result.size());
+        assertEquals(userJohn.getEmail(), result.get(0).getEmail());
+    }
+}