1.Look at the description of the class above in the document. Generally speaking, the first sentence of the class is a simple and direct introduction to this class.
2.Looking at this class document, we mainly need to use the object to call methods and properties
3. Pay attention to the construction method of this class (except for the tool class (without construction method), Math Arrays)
4. Take a look at the member variables. Because of the Java encapsulation mechanism, most member variables are private, and the jdk document will not list private members.
So look at the jdk document, the focus must be on the method of the class, the same private method is not in the jdk document, the method represents what this class/class object can do