hibernate - Could not determine type for: java.util.Set -

this classes user , catalog... 1 user have many catalog.

package com.egs.account.model;   import org.apache.commons.lang.builder.equalsbuilder;  import javax.persistence.*; import java.util.date; import java.util.set;  @entity @table(name = "user") public class user {     private long id;     private string username;     private string password;     private string passwordconfirm;     private string firstname;     private string lastname;     private date dateregistered;     private long skypeid;     private set<role> roles;      @onetomany(mappedby = "user", cascade = cascadetype.all)     private set<catalog> catalogs;      @id     @generatedvalue(strategy = generationtype.auto)     public long getid() {         return id;     }      public void setid(long id) {         this.id = id;     }      public string getusername() { return username; }      public void setusername(string username) {         this.username = username;     }      public string getpassword() {         return password;     }      public void setpassword(string password) {         this.password = password;     }      @transient     public string getpasswordconfirm() {         return passwordconfirm;     }      public void setpasswordconfirm(string passwordconfirm) {         this.passwordconfirm = passwordconfirm;     }      public string getfirstname() { return firstname; }      public void setfirstname(string firstname) { this.firstname = firstname; }      public date getdateregistered() { return dateregistered; }      public void setdateregistered(date dateregistered) { this.dateregistered = dateregistered; }      public long getskypeid() { return skypeid; }      public void setskypeid(long skypeid) { this.skypeid = skypeid; }      public string getlastname() { return lastname; }      public void setlastname(string lastname) { this.lastname = lastname; }      public set<role> getroles() {         return roles;     }      public void setroles(set<role> roles) {         this.roles = roles;     }      public set<catalog> getcatalogs() { return catalogs; }      public void setcatalogs(set<catalog> catalogs) { this.catalogs = catalogs; }      @override     public int hashcode() {         final int prime = 31;         int result = 1;         result = prime * result + ((id == null) ? 0 : id.hashcode());         result = prime * result + ((firstname == null) ? 0 : firstname.hashcode());         return result;     }      @override     public boolean equals(final object obj) {         if (!(obj instanceof user)) {             return false;         }         if (obj == this) {             return true;         }         final user other = (user) obj;         final equalsbuilder builder = new equalsbuilder();         builder.append(this.firstname, other.firstname);         builder.append(this.lastname, other.lastname);         builder.append(this.username, other.username);         builder.append(this.skypeid, other.skypeid);         return builder.isequals();     }      @override     public string tostring() {         return "userdocument [id=" + id + ", name=" + firstname + ", lastname="                 + lastname + ", username=" + username + "]";     } } 

and 1 catalog class.

 package com.egs.account.model;  import javax.persistence.*; import java.util.date;  @entity @table(name = "user") public class catalog {     @id     @generatedvalue(strategy = generationtype.auto)     private long id;     private string link;     private string comment;     private date insertdate;      @manytoone(optional = false)     @joincolumn(name = "user_id")     private user user;      @lob @basic(fetch = fetchtype.lazy)     @column(name="content", nullable=false)     private byte[] content;      public long getid() {         return id;     }      public void setid(long id) {         this.id = id;     }      public string getlink() { return link; }      public void setlink(string link) { this.link = link; }      public string getcomment() { return comment; }      public void setcomment(string comment) { this.comment = comment; }      public date getinsertdate() { return insertdate; }      public void setinsertdate(date insertdate) { this.insertdate = insertdate; }      public user getuser() { return user;}      public void setuser(user user) { this.user = user; }      public byte[] getcontent() { return content; }      public void setcontent(byte[] content) { this.content = content; } } 

and when running application, kind of exception.

caused by: org.hibernate.mappingexception: not determine type for: java.util.set, @ table: user, columns: [org.hibernate.mapping.column(catalogs)]

anybody please tell me wrong code.