#55 added initialization of fields in ConferenceDto

src/main/java/ru/ulstu/conference/model/ConferenceDto.java

@@ -13,6 +13,7 @@ import javax.persistence.TemporalType;
 import javax.validation.constraints.Size;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
@@ -25,22 +26,22 @@ public class ConferenceDto {
     @Size(min = 2, max = 400)
     private String title;
     @Size(max = 500)
-    private String description;
+    private String description = "";
     @Size(max = 255)
-    private String url;
-    private int ping;
+    private String url = "";
+    private int ping = 0;
     @Temporal(TemporalType.TIMESTAMP)
     @DateTimeFormat(pattern = "yyyy-MM-dd")
-    private Date beginDate;
+    private Date beginDate = new Date();
     @Temporal(TemporalType.TIMESTAMP)
     @DateTimeFormat(pattern = "yyyy-MM-dd")
-    private Date endDate;
+    private Date endDate = new Date();
     @NotEmpty
     private List<Deadline> deadlines = new ArrayList<>();
-    private Set<Integer> userIds;
-    private Set<Integer> paperIds;
-    private Set<PaperDto> papers;
-    private Set<UserDto> users;
+    private Set<Integer> userIds = new HashSet<>();
+    private Set<Integer> paperIds = new HashSet<>();
+    private Set<PaperDto> papers = new HashSet<>();
+    private Set<UserDto> users = new HashSet<>();
     private Integer filterUserId;
 
     public ConferenceDto() {