- 補全變量
- 實現接口
- 格式化字符串
System.out.printf("realName:" + u.getRealName() + "email: " + u.getEmail()); System.out.printf(String.format("realName:%semail: %s", u.getRealName(), u.getEmail()));
command + shift + A 3d
command + shift + A = (help -> dind action) code