Integer.parseInt(s.replaceAll("[\D]", ""))

s.matches("[\d]+[A-Za-z]?")

((Number)NumberFormat.getInstance().parse("123e")).intValue()

Scanner s = new Scanner(MyString);
s.nextInt();

int res = 0;
for (int i=0; i < str.length(); i++) {
    char c = s.charAt(i);
    if (c < '0' || c > '9') continue;
    res = res * 10 + (c - '0');
}

String something = "423e";
    int length = something.length();
    String result = "";
    for (int i = 0; i < length; i++) {
        Character character = something.charAt(i);
        if (Character.isDigit(character)) {
            result += character;
        }
    }
    System.out.println("result is: " + result);