Explicitly set strategy of generated value of entities' ID to IDENTITY

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/AbstractPhase.java

@@ -4,6 +4,7 @@ package cz.muni.ics.kypo.training.adaptive.domain;
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.Inheritance;
 import javax.persistence.InheritanceType;
@@ -17,7 +18,7 @@ import java.io.Serializable;
 public abstract class AbstractPhase implements Serializable {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     private String title;

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/DecisionMatrixRow.java

@@ -4,6 +4,7 @@ import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.ManyToOne;
 import java.io.Serializable;
@@ -12,7 +13,7 @@ import java.io.Serializable;
 public class DecisionMatrixRow implements Serializable {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     @Column(name = "order_in_phase", nullable = false)

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/Question.java

@@ -9,6 +9,7 @@ import javax.persistence.EnumType;
 import javax.persistence.Enumerated;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.ManyToMany;
 import javax.persistence.ManyToOne;
@@ -25,7 +26,7 @@ import java.util.Set;
 public class Question implements Serializable  {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     @Enumerated(EnumType.STRING)

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/QuestionChoice.java

@@ -4,6 +4,7 @@ import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.ManyToOne;
 import java.io.Serializable;
@@ -12,7 +13,7 @@ import java.io.Serializable;
 public class QuestionChoice implements Serializable {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     private String text;

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/QuestionPhaseRelation.java

@@ -5,6 +5,7 @@ import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.JoinColumn;
 import javax.persistence.JoinTable;
@@ -17,7 +18,7 @@ import java.util.Set;
 public class QuestionPhaseRelation implements Serializable {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     @Column(name = "order_in_questionnaire", nullable = false)

src/main/java/cz/muni/ics/kypo/training/adaptive/domain/Task.java

@@ -4,6 +4,7 @@ import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.ManyToOne;
 import java.io.Serializable;
@@ -13,7 +14,7 @@ import java.io.Serializable;
 public class Task implements Serializable {
 
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     private String title;