Inputting and validating the email address in JAVA -

i have written below code unable make loop if input entered false.kindly me.

system.out.println("please enter email address ex:xyz@gmail.com");         string emailaddress=name.nextline();          string email_regex = "[a-z]+[a-za-z_]+@\b([a-za-z]+.){2}\b?.[a-za-z]+";         string teststring = emailaddress;         boolean b = teststring.matches(email_regex);         system.out.println("string: " + teststring + " :valid = " + b);         system.out.println("email address " +emailaddress); 

here goes 3 functions :

public class abc{  public static void main(string[] args){    inputemail(); }  public boolean checkemailvalidity(string emailaddress){     string email_regex = "[a-z]+[a-za-z_]+@\b([a-za-z]+.){2}\b?.[a-za-z]+";    boolean b = teststring.matches(email_regex);    return b; }  public void inputemail(){         system.out.println("please enter email address ex:xyz@gmail.com");         string emailaddress=name.nextline();         boolean = checkemailvalidity(emailaddress);        if(a){           system.out.println("valid email");         } else {           system.out.println("invalid email");            inputemail();        } } 

}

here updated answer :

package smsmain;  import java.util.scanner;       public class cstudentinfo {          public static void createstudent() {            scanner name = new scanner(system.in);            system.out.println("please enter first name:");                   while(!name.hasnext("[a-za-z]+")){                   system.out.println("please re-enter name, use alphabets)                   system.out.println("please enter first name:");                     name.nextline();                 }          string firstname=name.nextline();          system.out.println("your firstname " + firstname);         inputemail();