Java. lang Package Overview (1)

Author: Source: Java Research Organization

I. Interface
Java. Lang. appendable

Append Interface. The object instance of the class that implements this interface has the ability to append characters or character sequences to it. Classes that want to receive formatter output must implement this interface.
Java. Lang. charsequence
Charsequence refers to the readable character sequence. This interface provides a unified method for read-only access to various types of character sequences.
Java. Lang. cloneable
Yes
Clone interface. The class implementing this interface can be cloned. You can use the object. Clone () method to copy the domain (FIELD) of the Instance Object of the class to another instance object of the same class one by one.
. If you use the object. Clone () method to clone instance objects of classes that do not implement this interface, clonenotsupportedexception will be triggered
.
Java. Lang. Comparable
Comparable interfaces. The two instance objects of the class implementing this interface can be compared. Negative Numbers (-1), 0, and positive numbers (1) indicate the relationship between the compared object and the compared object, which is less than, equal to, or greater. You can sort multiple instance objects of classes that implement this interface.
Java. Lang. iterable
Iteratable interface. Classes that implement this interface are generally used as containers and provide the ability to access the contained objects in turn.
Java. Lang. readable
Readable interface. The customer object can read characters from the instance object that implements the interface class.
Java. Lang. runable
Runable interface. The instance object of the class implementing this interface will be run in a separate thread. Classes without extension threads can implement this interface to develop multi-threaded services.
Java. Lang. thread. uncaughtexceptionhandler
The thread does not capture the exception Controller Interface. When an exception is thrown during thread execution without capturing it, the class implementing this interface can be used as a controller to handle this situation.

Ii. Category
Java. Lang. Boolean
Class that visualizes the original data type boolean. In addition to a Boolean value, the instance object of this class also provides methods for processing boolean values, such as conversion between Boolean strings.
Java. Lang. byte
Class that visualizes the original data type bytes. In addition to a byte value, the instance object of this class also provides methods for converting bytes to other types and processing bytes.
Java. Lang. Character
Set
Class of the original data type char. In addition to a char value, the instance object of this class also provides a method to process characters. Java 2 platform in character array, string or
Use UTF-16 to express characters in stringbuffer. The UTF-16 is expressed with 16 to 21 bits, from/u0000 to/u10ffff. /U0000
/Uffff indicates the basic 16-bit characters,/u10000 to/u10ffff indicates the auxiliary character (supplymentary characters ). Secondary character
A high-surrogate is combined with a low-surrogate. Use a/ud800
/Udbff character representation; low substitution character represents a character between/udc00 and/udfff.
Assume that a represents the code point value of the secondary character (SC), and B represents
The Unicode code point value of SC; C indicates the code point value of SC. Then the following equation is
Li: A = (B-0xd800) <10 + (c-0xdc00) + 0x10000
When Unicode is restored to readable characters, when and only when the current character is a high-bit substitution character and the next character is a low-level substitution character, the two consecutive characters are interpreted as secondary characters.
Java. Lang. character. subset
This class is used to express a specific subset of a Unicode Character Set.
Java. Lang. character. unicodeblock
The instance object of this class represents a family of related sub-UNICODE character sets. These subcharacter sets generally serve the same purpose.
Java. Lang. Class
The instance object of this class represents the class or interface in the Java application. This class does not have a public constructor, so it cannot be automatically instantiated by the Java virtual machine, but by the classloader.