Using Java to implement object-oriented fifth chapter

The fifth chapter anomaly one, exception overview

Overview: Exceptions are abnormal events that occur during a program's run, and he interrupts a running program

Second, exception handling

1. Keyword: Try Catch finally throw throws

2.Try: Put the code that might appear to be abnormal in the Try

3.Catch: Catching exceptions

4.Finally: Code that executes regardless of whether there is an exception

5.Throw: Always appear in the method body

6.Throws: Always appears in the declaration of the method, using the various exceptions that indicate that the modification method may be thrown

Three: Common exceptions

Exception: Root class for exception hierarchies

ArithmeticException: The case of arithmetic error,

ArrayIndexOutOfBoundsException: Array greater than or less than the size of the actual array

NullPointerException: Attempting to access a null object member

ClassNotFoundException: To get the data type mismatch with the actual input type

IllegalArgumentException: Illegal parameters accepted by method

Four: log4i Record day file information

The log file has an output priority:

From high to Low: Error warn info debug

Using Java to implement object-oriented fifth chapter