import java.io.*;
public class Practive{
	public static void main (String[] args){
		strmanip();
	}
	static void strmanip(){
		String name ="";
		String password="";
		try{
			BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
			System.out.println("Create a new user name");
			name = read.readLine();
			System.out.println("Create a new password");
			password=read.readLine();		
		}catch (IOException e){}	
		if (password.length()>8)
			System.out.println("Welcome "+ name +"!");
		else System.out.println("Your password must be greater than 8 characters");
		
	}
}

a piece of code

[Note] BufferedReader and length()

Java