### Question:
StringUtils { public static boolean isPrintableString(String str) { for (int i = 0; i < str.length(); i++) { if (!isPrintableChar(str.charAt(i))) { return false; } } return true; } private  StringUtils(); static boolean isPrintableString(String str); static boolean isValidMetricName(String metricName); static final int METRIC_NAME_MAX_LENGTH; }### Answer:
@Test void isPrintableString() { assertThat(StringUtils.isPrintableString("abcd")).isTrue(); assertThat(StringUtils.isPrintableString("\2ab\3cd")).isFalse(); }