Remove all chars in java string, except '0' and '1' -

how can remove characters being neither '0' nor '1' in string, final string consists of 0s , 1s? i'm using java 8.

my solution loop (i think it's not efficient way):

string before = "012940124810"; string after = new string();  for(int = 0; < before.length();  i++) {   if(before.charat(i) == '0' || before.charat(i) == '1') {     after += before.charat(i);   } } 

you can use regex , replaceall method

 string out = str.replaceall("[^01]", "");