### Question:
ParserHelper { public static boolean isDouble(String s) { return s != null && doublePattern.test(s); }  static boolean isDouble(String s); static boolean isInteger(String s); static boolean isInteger(String s, int radix);  }### Answer:
@Test public void testIsDouble() { assertTrue(ParserHelper.isDouble("1.0")); assertFalse(ParserHelper.isDouble("Z2")); }