Knowledge Point Records-pending finishing

1. Overloading and rewriting

Overload:

The number or type of arguments is different, regardless of the return value type. (if the parameter and name are the same, only the return value is different, a compilation error will occur)

Override (Overwrite):

The method name is the same and the parameter type is the same. The subclass return type is less than or equal to the parent class method return type, the subclass throws an exception less than equals the parent class method throws an exception, and the subclass access permission is greater than or equal to the parent class method access. 2. Thread Safety (thought: Similar to multi-transaction concurrent access issues: missing changes, read dirty data, non-repeatable read, Phantom Read) 3. Static code block http://bbs.itheima.com/ thread-115483-1-1.htmlhttp://www.jb51.net/article/36038.htm 4.this related knowledge http://www.cnblogs.com/ Java-class/archive/2012/12/19/2825463.htmlhttp://my.oschina.net/kalo/blog/333202http://wenku.baidu.com/link? url=0o8bsjt1wodmp2gcj1wsxqmxodopr1_9gbpu_nz3hkwusdpofrrru9oalgxgas8c4-unmezjajrjl__ 4ded7q7rez-mcnpkklu8iqzmijrohttp://blog.csdn.net/anmei2010/article/details/4091227 5.

Knowledge Point Records-pending finishing