fix deprecated imports

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

@@ -2,7 +2,6 @@ package ru.ulstu.conference.model;
 
 import org.hibernate.annotations.Fetch;
 import org.hibernate.annotations.FetchMode;
-import org.hibernate.validator.constraints.NotBlank;
 import org.springframework.format.annotation.DateTimeFormat;
 import ru.ulstu.core.model.BaseEntity;
 import ru.ulstu.deadline.model.Deadline;
@@ -20,6 +19,7 @@ import javax.persistence.OrderBy;
 import javax.persistence.Table;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
+import javax.validation.constraints.NotBlank;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;

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

@@ -2,13 +2,13 @@ package ru.ulstu.conference.model;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
-import org.hibernate.validator.constraints.NotEmpty;
 import org.springframework.format.annotation.DateTimeFormat;
 import ru.ulstu.deadline.model.Deadline;
 import ru.ulstu.paper.model.Paper;
 
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
+import javax.validation.constraints.NotEmpty;
 import javax.validation.constraints.Size;
 import java.util.ArrayList;
 import java.util.Date;

src/main/java/ru/ulstu/students/model/Task.java

@@ -2,7 +2,6 @@ package ru.ulstu.students.model;
 
 import org.hibernate.annotations.Fetch;
 import org.hibernate.annotations.FetchMode;
-import org.hibernate.validator.constraints.NotBlank;
 import ru.ulstu.core.model.BaseEntity;
 import ru.ulstu.deadline.model.Deadline;
 import ru.ulstu.tags.model.Tag;
@@ -20,6 +19,7 @@ import javax.persistence.OneToMany;
 import javax.persistence.OrderBy;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
+import javax.validation.constraints.NotBlank;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;

src/main/java/ru/ulstu/students/model/TaskDto.java

@@ -3,10 +3,10 @@ package ru.ulstu.students.model;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import org.apache.commons.lang3.StringUtils;
-import org.hibernate.validator.constraints.NotEmpty;
 import ru.ulstu.deadline.model.Deadline;
 import ru.ulstu.tags.model.Tag;
 
+import javax.validation.constraints.NotEmpty;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;

src/main/java/ru/ulstu/tags/model/Tag.java

@@ -2,12 +2,12 @@ package ru.ulstu.tags.model;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
-import org.hibernate.validator.constraints.NotEmpty;
 import ru.ulstu.core.model.BaseEntity;
 
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.Table;
+import javax.validation.constraints.NotEmpty;
 import javax.validation.constraints.Size;
 
 @Entity

src/main/java/ru/ulstu/timeline/model/Event.java

@@ -1,6 +1,5 @@
 package ru.ulstu.timeline.model;
 
-import org.hibernate.validator.constraints.NotBlank;
 import ru.ulstu.core.model.BaseEntity;
 import ru.ulstu.paper.model.Paper;
 import ru.ulstu.user.model.User;
@@ -17,6 +16,7 @@ import javax.persistence.ManyToOne;
 import javax.persistence.OneToMany;
 import javax.persistence.Temporal;
 import javax.persistence.TemporalType;
+import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
 import java.util.Date;
 import java.util.List;