how to create a custom datatype in java? -

i want create custom datatype in java,for example datatype email , having following method isvalidate(string email),isemailexist(string email),getdomain(string email), id(string email),just integer class in java.

integer class , can initialise object of integer class follows:

integer = 100;

i created class email , want initialise follows email e = "sam";

how can perform functionality in email class.

import java.util.stringtokenizer; import java.util.regex.matcher; import java.util.regex.pattern;
  
public class email {    private string email;     public email(string email)     {         this.email=email;     }
  
email() {  }  public boolean isvalid(string email) { 
  
string lasttoken = null;   pattern p = pattern.compile(".+@.+\.[a-z]+");    // match given string pattern    matcher m = p.matcher(email);    // check whether match found    boolean matchfound = m.matches();    stringtokenizer st = new stringtokenizer(email, ".");    while (st.hasmoretokens())    {       lasttoken = st.nexttoken();    }
  
if (matchfound && lasttoken.length() >= 2       && email.length() - 1 != lasttoken.length())    {
  
  return true; 
  
}    else        return false;
  
} 
  
public string tostring() {     return email;     }
  
}
  

thanks

create email class. java 101; book or free tutorial of java language started.