Write a Java method onlyDigits that takes a string as a parameter. The method should remove from the string all characters, which are not digits, and return a string that contains only digits.

public static String onlyDigits (String in) {

String digitsOnly = in. replaceAll ("[^0-9]", "");

return digitsOnly;

}

A Complete program is wrtten in the explanation section

Explanation:

public class TestClass {

public static void main (String[] args) {

String a = "-jaskdh2367sd. 27askjdfh23";

System. out. println (onlyDigits (a));

}

public static String onlyDigits (String in) {

String digitsOnly = in. replaceAll ("[^0-9]", "");

return digitsOnly;

}

}

The output: 23672723

The main logic here is using the Java replaceAll method which returns a string after replacing all the sequence of characters that match its argument, regex with an empty string