ентити наследуются от суперкласса. Исправил связи

src/main/java/ru/ldeloff/hedgehogcloud/entity/BaseEntity.java

@@ -0,0 +1,33 @@
+package ru.ldeloff.hedgehogcloud.entity;
+
+import com.sun.istack.NotNull;
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.domain.Persistable;
+
+import javax.persistence.Id;
+import javax.persistence.MappedSuperclass;
+import javax.persistence.Transient;
+import java.util.UUID;
+
+@NoArgsConstructor
+@Setter
+@MappedSuperclass
+@EqualsAndHashCode
+public class BaseEntity implements Persistable<String> {
+    @Id
+    protected String id = UUID.randomUUID().toString();
+    @Transient
+    private Boolean justCreated = false;
+
+    @Override
+    public String getId() {
+        return null;
+    }
+
+    @Override
+    public boolean isNew() {
+        return justCreated;
+    }
+}

src/main/java/ru/ldeloff/hedgehogcloud/entity/RoleEntity.java

@@ -6,10 +6,7 @@ import lombok.Setter;
 import org.springframework.security.core.GrantedAuthority;
 import org.springframework.transaction.annotation.Transactional;
 
-import javax.persistence.Entity;
-import javax.persistence.Id;
-import javax.persistence.Table;
-import javax.persistence.Transient;
+import javax.persistence.*;
 import java.util.Set;
 
 @NoArgsConstructor
@@ -17,13 +14,15 @@ import java.util.Set;
 @Setter
 @Entity
 @Table(name = "roles")
-public class RoleEntity implements GrantedAuthority {
-    @Id
-    private String id;
+public class RoleEntity extends BaseEntity implements GrantedAuthority {
     private String name;
     @Transient
+    @ManyToMany
     private Set<UserEntity> users;
 
+    public String getName() {
+        return name;
+    }
     @Override
     public String getAuthority() {
         return getName();

src/main/java/ru/ldeloff/hedgehogcloud/entity/UserEntity.java

@@ -1,14 +1,12 @@
 package ru.ldeloff.hedgehogcloud.entity;
 
-import lombok.AccessLevel;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
-import lombok.Setter;
+import lombok.*;
 import org.springframework.security.core.GrantedAuthority;
 import org.springframework.security.core.userdetails.UserDetails;
 
 import javax.persistence.*;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Set;
 
 @NoArgsConstructor
@@ -16,15 +14,17 @@ import java.util.Set;
 @Setter
 @Entity
 @Table(name = "users")
-public class UserEntity implements UserDetails {
-    @Id
-    @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private String id;
+public class UserEntity extends BaseEntity implements UserDetails {
     private String username;
     private String password;
 
     @ManyToMany(fetch = FetchType.EAGER)
-    private Set<RoleEntity> roles;
+    @JoinTable(
+            name = "users_roles",
+            joinColumns = { @JoinColumn(name = "user_id") },
+            inverseJoinColumns = { @JoinColumn(name = "role_id") }
+    )
+    private Set<RoleEntity> roles = new HashSet<>();
 
     @Override
     public Collection<? extends GrantedAuthority> getAuthorities() {