"DAY7" on the seventh day of abnormal learning notes

Abnormal

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Two subcategories of 1.throwable exception and Error.

2. Use the throw key to throw an exception object.

throw new Xxxxexception (...);

3. Method definitions can be added when throwing exception declarations

public void Mname (...) throws Xxxxexception,.... {...}

4.RuntimeException can not throw a declaration when the method is defined.

5.RuntimeException throws can be captured without the use of try-catch-finally.

6. Exception is not catch processing, will be thrown further.

7. When the method overrides, you cannot append a new exception to the throw declaration, but you can throw a subclass of the exception that is declared by the overridden method.

on the difference between throws and throw

Throws is used to denote an exception that is exposed by a function.

Throw is used to throw the exception object throw new Xxexception (..)

Throws used on functions, followed by the exception class name

Throw is used inside a function, followed by an object with an exception

exception Handling:

try{//method to be detected, object code.

}

catch (Exception e) {//How to handle these exceptions.

}

finally{//code that is bound to execute after the exception is processed (with or without exceptions).

}

Example:

To use on a method function: throws Exception

Inside the method: Throw object New Xxexcepton ()

Write to try in Call: Try{}catch () {}finally{}

member access rules

	Public	Protected	Default	Private
In the same	√	√	√	√
In the same package	√	√	√
Sub-class	√	√
Different packages	√

Package

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packages, folders.

Java/lang/xxxx

Jar:java Archieve,java archive file.

Java/lang/object.class

Full name, complete class name: Java.lang.Object java/lang/object

Specify the class file directory at compile time using the- d parameter: java-d xx/xxx Packagedemo.java

The runtime specifies the directory where the class file is locatedusing the-CP parameter: JAVA-CP xx/xx A

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"DAY7" on the seventh day of abnormal learning notes