title: Cannot instantiate the type userSQLOpenHelper and I do not know why
body: <p>In my MainActivity.java I get this error "Cannot instantiate the type userSQLOpenHelper". at new userSQLOpenHelper(this). Can someone tell me what I am missing or doing wrong?</p>
  
  <p>MainActivity.java </p>
  
  <pre><code>userSQLOpenHelper db = new userSQLOpenHelper(this);             
  // add user
  db.addUser(new user(name1,born1,sex,passwd,email1));   
  </code></pre>
  
  <p>user.java</p>
  
  <pre><code>public final class user {
  
      private int id;
      private String name;
      private String born;
      private String sex;
      private int password;
      private String email;
  
          // This is recommended to prevent someone from accidentally instantiating the user class,
      public user() {}
  
      /* Inner class that defines the table contents */
      public user(String name, String born, String sex, int password, String email)      {
          // super();
          this.name = name;
          this.born = born;
          this.sex = sex;
          this.password = password;
          this.email = email;
      }
  
      @Override
      public String toString() {
          return "user [id=" + id + ", name=" + name + ", born=" + born + ", sex=" + sex + ", password=" + password
              + ", email=" + email + "]";
      }
  
      public int getId(){
          return this.id;
      }
  
      public void setId(int id){
          this.id = id;
      }
  
      public String getName(){
          return this.name;
      }
  
      public void setName(String name){
          this.name = name;
      }
  
      public String getBorn(){
          return this.born;
      }
  
      public void setBorn(String born){
          this.born = born;
      }
  
        public String getSex(){
          return this.sex;
      }
  
      public void setSex(String sex){
          this.sex = sex;
      }
  
        public int getPassword(){
          return this.password;
      }
  
      public void setPassword(int password){
          this.password = password;
      }
  
      public String getEmail(){
          return this.email;
      }
  
      public void setEmail(String email){
          this.email = email;
      }
  }
  </code></pre>
  
  <p>userSQLOpenHelper.java</p>
  
  <pre><code>public abstract class userSQLOpenHelper extends SQLiteOpenHelper {
  
      // Table name
      private static final String TABLE_USERS = "users";
  
      // Table Columns names
      private static final String USER_ID = "id";
      private static final String USER_NAME = "name";
      private static final String USER_BORN = "born";
      private static final String USER_SEX = "sex";
      private static final String USER_PASSWORD = "password";
      private static final String USER_EMAIL = "email";
  
      //private static final String[] COLUMNS = {USER_ID,USER_NAME,USER_BORN,USER_SEX,USER_PASSWORD,USER_EMAIL};
  
      // Database Version
      private static final int DATABASE_VERSION = 1;
  
      // Database Name
      private static final String DATABASE_NAME = "userDB";   
  
    public userSQLOpenHelper(Context context) {
      super(context, DATABASE_NAME, null, DATABASE_VERSION);  
    }
  
  
      @Override
    public void onCreate(SQLiteDatabase db) {
      // SQL statement to create user table
      String CREATE_USER_TABLE = "CREATE TABLE users ( " +
              "id INTEGER PRIMARY KEY AUTOINCREMENT, " + 
              "name TEXT NOT NULL, "+ 
              "born TEXT NOT NULL, " +
              "sex TEXT NOT NULL, " +
              "password INTERGER NOT NULL, " +
              "email TEXT NOT NULL )";
  
      // create books table
      db.execSQL(CREATE_USER_TABLE);
  
    }
  
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      // Drop older books table if existed
      db.execSQL("DROP TABLE IF EXISTS books");
  
      // create fresh books table
      this.onCreate(db);
    }
  
  
    public void addUser(user user){
      SQLiteDatabase db;
       //get reference to writable DB
       db = this.getWritableDatabase();
  
      //create ContentValues to add key "column"/value
      ContentValues values = new ContentValues();
      values.put(USER_NAME, user.getName()); 
      values.put(USER_BORN, user.getBorn()); 
      values.put(USER_SEX, user.getSex()); 
      values.put(USER_PASSWORD, user.getPassword()); 
      values.put(USER_EMAIL, user.getEmail()); 
  
        // insert
      db.insert(TABLE_USERS, null, values); 
  
      // close
      db.close(); 
      }
  
  }
  </code></pre>