java - all substrings in a string

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import java.util.ArrayList; import java.util.List; public class _String { /** * Print all substrings of a string */ public static List<String> all_substrings_in_a_string(String str) { List<String> list = new ArrayList<>(); char[] chars = str.toCharArray(); int size = 0; while(size++ < chars.length) { char[] c = new char[size]; for (int i = 0; i < chars.length; i++) { if(i + c.length <= chars.length) { for (int j = 0; j < c.length; j++) { c[j] = chars[i+j]; } list.add(new String(c)); } } } return list; } }