java exception overview
catalogue 1, What is an exception 2, Exception architecture 3, Exception handling mechanism 4, Custom exception 1, What is an exception In actual work, the situation encountered can not be very perfect. For example, for a module you write, the user input does not necessarily meet your requiremeUTF-8...
Posted by DeGauss on Mon, 20 Sep 2021 19:11:18 +0530
Xi - IO flow
1, File abstract class Abstract representation of file and directory pathnames. The File or folder or path represented by the File class does not necessarily exist. This class is mainly used for: Creation and deletion of filesCreation and deletion of folders 1. Relative / absolute path object UTF-8...
Posted by Ice on Tue, 21 Sep 2021 02:03:02 +0530
Java8 - functional interface and Lambda
Catalogue of series articles 1. Functional interface 1.1 concept of functional interface In an interface, there can only be one abstract method, and there can be other non abstract methods, such as static and default methods. Defining a functional interface is simple: public interface MyFunctioUTF-8...
Posted by zkoneffko on Thu, 23 Sep 2021 15:34:09 +0530
Talk about various internal classes of java
1, Member inner class public class OutClass { private int age = 1; private static int staticAge = 2; private static void test(){ System.out.println("Static test"); } class Inner{ public void show(){ System.out.println(age); //1 } } static class staticInner{ public void show(){ System.out.printlUTF-8...
Posted by Vigilant Psyche on Thu, 30 Sep 2021 04:13:12 +0530
[Java] library management system (Rookie version)
preface In the previous blogs, Shanju analyzed classes and objects, introduced packages, analyzed the basic characteristics of object-oriented, and vividly explained what interfaces are. In the process of summarizing, it has benefited a lot. This time, Shanju will integrate these things and wrUTF-8...
Posted by GimbaL on Sat, 02 Oct 2021 01:28:15 +0530
XVI - DQL and DDL
1, DQL: query essence (select) Through the select statement, a "virtual table" - resultset, which is subordinate to the data table, is obtained 1. According to the nature of the select operation, it can be divided into: Clause: where/having /limit(o,l) / ORDER BY(desc,asc) / GROUP BY/ Method: UTF-8...
Posted by jphilapy on Wed, 06 Oct 2021 04:14:41 +0530
XIV - database operation
preface In the UserManager program, the storage of data is persisted through files. If there are more types of data and more interactions For example: add Fund - > user buys fund There may be data redundancy 1. Background Data persistence, large amount of data, user demand Database programmingUTF-8...
Posted by hiprakhar on Wed, 06 Oct 2021 06:09:30 +0530
Java multithreading -- 1
Java multithreading (Thread) 1, Basic concepts: program, process, thread program: a set of instructions written in a certain language to complete a specific task. That is, a piece of static code, a static objectProcess: an execution process of a program, or a running program. It is a dynamic prUTF-8...
Posted by namasteaz on Tue, 12 Oct 2021 01:52:51 +0530
Java multithreading -- 2
4, Thread synchronization Why do I need thread synchronization? The uncertainty of multi thread execution leads to the instability of execution results;The sharing of ledger by multiple threads will cause incomplete operation and destroy data. Example: create three windows to sell tickets, andUTF-8...
Posted by dazz_club on Tue, 12 Oct 2021 03:44:29 +0530
30,000-word Java web tutorial
1. Basic concepts 1.1. Preface web development: Web, the meaning of the web page, www.baidu.comStatic web html，cssThe data available to everyone will never change! Dynamic web Taobao, almost all websites;The data available to everyone will always change, and everyone will see different informUTF-8...
Posted by smook on Thu, 14 Oct 2021 23:02:09 +0530