Yor implementation (the one in the comment) is full of bugs. Hopefully I've fixed all of them. Try
import java.util.Scanner;
public class PasswordValidator
{
public static void main (String[] args)
{
Scanner input = new Scanner (System.in);
boolean isSecure =isSecurePassword( input.nextLine());
System.out.println(isSecure);
}
public static boolean isSecurePassword (String password)
{
if ( password.length() < 10) return false;
boolean uppercase=false;
boolean lowercase=false;
boolean digit=false;
for(char c : password.toCharArray())
{
if (c >='a'&& c <='z')
lowercase = true;
else if (c >='A'&& c <='Z')
uppercase =true;
else if ( c >='0' && c<='9')
digit = true;
}
return (uppercase && lowercase && digit);
}
}