Java se -- phase 1 2

Object oriented programming (basic) Object oriented and process oriented (understanding) 1. Process oriented: it emphasizes the functional behavior, taking the function as the minimum unit and considering how to do it.2. Object oriented: emphasize the objects with functions, take the class / object as the minimum unit, and consider who will d ...

Posted by supanoob on Sun, 26 Dec 2021 22:29:23 +0100

Java se -- abstract classes and interfaces

abstract class summary Abstract class introduction The method in the parent class is overridden by its subclasses, and the implementation of subclasses is different. Then the method declaration and method body of the parent class only have meaning, while the method body has no meaning (because the subclass object will call its own overridden ...

Posted by markwillis82 on Sun, 26 Dec 2021 13:28:14 +0100

[Java SE] 8. Common Java classes

8.1 string related classes Properties of String: All string literals (such as "abc") in Java programs are implemented as instances of this class Is a final class that represents an immutable character sequence and cannot be inherited String implements Java io. Serializable interface, indicating that the string can be seria ...

Posted by MorganM on Sat, 25 Dec 2021 22:43:24 +0100

Detailed explanation of Synchronized learning notes

Chapter 1: three problems in concurrent programming 1. Visibility target Learn what visibility issues are Visibility concept Visibility: when one thread modifies a shared variable, the other needs to get the latest modified value immediately. Visibility presentation Case demonstration: one thread loops according to the flag and while of ...

Posted by Otiose Dodge on Fri, 24 Dec 2021 19:34:37 +0100

Java se -- phase 2 3

aggregate Collection usage scenario Classification of sets Java collections can be divided into Collection and Map systems Collection interface: single column data, which defines the collection of methods to access a group of objects List: an ordered and repeatable collection of elementsSet: an unordered and non repeatable set of elem ...

Posted by coreyp_1 on Thu, 23 Dec 2021 17:22:33 +0100

Java se -- phase 2

1. Enumerations and annotations 1. Enumeration introduction Enumeration classes [pieces: one by one: examples, that is, the classes that instantiate specific objects one by one are called enumeration classes] 2. Custom class implementation enumeration You do not need to provide a setXxx method, because enumeration object values are usually ...

Posted by suz_1234 on Wed, 22 Dec 2021 23:47:10 +0100

[java basic syntax] explain the Lambda expression of Java in detail

1. Introduction Lambda expressions are an important new feature in Java se 8Lambda expressions allow you to use expressions instead of functional interfacesLambda expressions, like methods, provide a list of normal parameters and a body that uses these parametersLambda expression can be regarded as an anonymous function based on λ ...

Posted by hammadtariq on Tue, 21 Dec 2021 15:09:44 +0100

Shang Xuetang__ Baizhan programmer__ Question 1573 ------ Chapter 9 IO stream technology

1. What does IO mean? What does data source mean?         Input,Output; Input and output Data source: data source 2. What is the difference between byte stream and character stream? What is the difference between an input stream and an output stream? Character stream and byte stream are a division of stream, which are di ...

Posted by mcog_esteban on Mon, 20 Dec 2021 04:21:34 +0100

[java basic syntax] detailed enumeration of Java

1. Definitions Java enumeration is a special class, which generally represents a set of constants, such as 4 seasons of a year, 12 months of a year, 7 days of a week, Southeast, northwest and so on. Similarly, when a variable has several fixed possible values, it can be defined as an enumeration type Definition form: Modifier enum Enume ...

Posted by Rdam on Mon, 20 Dec 2021 04:03:08 +0100

X - multithreading

problem 1. If there is a very time-consuming calculation in the business: + 1 million operations (the speed is slow and the execution time becomes longer) 2. Multiple execution units in the program at the same time? And they are all cycles (dead cycles) 1, Thread 1. Background java supports multithreading (JS php) and a large number ...

Posted by psy on Fri, 17 Dec 2021 16:41:52 +0100