Programmer Think

MacOS java development 2 variables and constants constant Constants: data that cannot be changed Data, keywords and identifiers are all components of JAVA programs Constant category: Integer 100, 23, 1 Decimals 3.14, 21.231 Character - enclosed in single quotation marks, can only write one character and must have a value String - enclos ...

Integer type (byte, short, int, long) Floating point type (float, double) Character char boolean 1. Integer type Integer type is used to store integer (no decimal part) values, which can be positive or negative. Integer data can be divided into byte, short, int and long according to its memory size. Different data types have diff ...

catalogue 01 string related 1.1 overview of string class 1.2 creation of string object  1.2.2  String str1 = “abc”; And String str2 = new String("ABC"); What's the difference? 1.2.3 memory parsing of string with different splicing methods 1.2.4 an interview question 1.3 common methods in string 1.3.1 ...

RabbitMQ is used as the message queue in the project. I have encountered the loss of messages. I hereby record it. Write in front First, let's talk about the three semantics in MQTT protocol, which is very important. In MQTT protocol, three quality of service standards that can be provided when delivering messages are given. The thre ...

1. General Class loader is the premise for JVM to execute class loading mechanism. Functions of ClassLoader: ClassLoader is the core component of Java. All classes are loaded by ClassLoader. ClassLoader is responsible for reading the binary data stream of Class information into the JVM through various ways and converting it into a Java co ...

1.0 transfer to the next platform. For the things written before, they have recently moved them to the Jane book, and they will write on the Jane book in the future. 2.0 in Java, the format of creating objects is: Class name object name = new class name (); For example: JFrame jf = new JFrame(); When an object is created, it often needs to do ...

1, Connect the html page to the server First, in the previous blog, I wrote the html version of the confession wall Now, you need to connect the html version of the confession wall to the back-end server The code is as follows: import com.fasterxml.jackson.databind.ObjectMapper; import javax.servlet.annotation.WebServlet; import java ...

1, Introduction to network programming Network programming: under the network communication protocol, data can be exchanged between programs running on different computers to realize network interconnection 1.1 three elements of network programming IP address: to enable computers in the network to communicate with each other, you must sp ...

Okhttp interceptor details Okhttp interceptor introduction Concept: interceptor is a powerful mechanism provided in Okhttp. It can realize network monitoring, request and response rewriting, request failure retry and other functions. Let's first understand the system interceptor in Okhttp: RetryAndFollowUpInterceptor: it is responsible for i ...

Basic introduction A coded block, also known as an initialization block, is a member of a class [that is, a part of a class], which is similar to a method. It encapsulates logical statements in the method body and is surrounded by {}. But unlike methods, there is no method name, no return, no parameters, only method body, and it is not explici ...