### Question:
RegUtil { public final static boolean isEmail(String email) { if (email == null || email.length() < 1 || email.length() > 256) { return false; } Pattern pattern = Pattern.compile(REG_EMAIL); return pattern.matcher(email).matches(); }  final static boolean isNumeric(String src); final static boolean isABC(String src); final static boolean isFloatNumeric(String src); final static boolean isMatche(String str, String reg); final static int countSubStrReg(String str, String reg); final static boolean isEmail(String email); static final String REG_ALNUM; static final String REG_ALPHA; static final String REG_ASCII; static final String REG_BLANK; static final String REG_CNTRL; static final String REG_DIGITS; static final String REG_GRAPH; static final String REG_LOWER; static final String REG_PRINT; static final String REG_PUNCT; static final String REG_SPACE; static final String REG_UPPER; static final String REG_XDIGIT; static final String REG_SPACE_LINE; static final String REG_SPACE_POINT; static final String REG_HTML; static final String REG_EMAIL; static final String REG_FIXED_TELEPHONE; static final String REG_POSTALCODE; static final String REG_IDENTIFICATION_CARD; static final String REG_URL; static final String REG_MOBILE_TELEPHONE; static final String REG_LEGAL_ACCOUNT; static final String REG_IP; }### Answer:
@Test public void testisEmail() { assertEquals(true, RegUtil.isEmail("12@1.com")); assertEquals(false, RegUtil.isEmail("12#1.com")); }