PoolUtil { protected static String safePrint(Object... o){ StringBuilder sb = new StringBuilder(); for (Object obj: o){ sb.append(obj != null ? obj : "null"); } return sb.toString(); }  static String fillLogParams(String sql, Map<Object, Object> logParams); static String stringifyException(Throwable t); static SQLException generateSQLException(String reason, Throwable t);  }
@Test public void testPoolUtilSafePrint() { assertEquals("nullhello", PoolUtil.safePrint(null, "hello")); new PoolUtil(); }