class Minimal
{
    static String RemovePunct(String input) 
    {
        char[] output = new char[input.length()];
        int i = 0;
 
        for(char ch : input.toCharArray())
        {
            if (Character.isLetterOrDigit(ch) || Character.isWhitespace(ch)) 
            {
                output[i++] = ch;
            }        
        }
 
        return new String(output);
    }
 
    public static void main (String [] Argv) {
        String s = RemovePunct("This is (a) test string.");
        System.out.println("'" + s + "'");
    }
}

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