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Original website: Java multithreading -- ReentrantLock -- use / example / principle_ CSDN blog brief introduction explain          This article introduces ReentrantLock (reentrant exclusive lock) in Java's JUC. Including: usage and principle. summary         ReentrantLock is mainly implemented ...

Physical pixel & Physical pixel ratio Physical pixels refer to the smallest particles displayed on the screen, which are physically real. It's set at the factory. (resolution)When we develop, 1px is not necessarily equal to 1 Physical pixelOn the PC side page, one px is equal to one physical pixel, but the mobile side is differentThe numbe ...

Click is the most common and important means of interaction. The following describes how to click RecyclerView settings. Here is a common implementation, namely listener mode.When a user clicks an item, the app can respond accordingly. Here we use the method of adding click listeners to achieve this effect.Listener mode is widely used in Androi ...

Preface Lifecycle of components and associated hook functions text Lifecycle of components: The life cycle is the entire process from creation of a component to not running unloaded from a page. There are many functions that run throughout the life cycle, which are hook functions. Only class components have a life cycle. Hook function at cre ...

Basic concepts DB:DataBase (database, which actually exists as a file on the hard disk) DBMS: DataBase Management System MySQL Oracle SQL: structured query language, is a standard general language. When the SQL statement is executed, it will actually be compiled internally before executing the SQL. DBMS is responsible for executing SQL stateme ...

abstract The docking students provide a jar, and the bean s in it are 4-level nested, and there is no document. Looking at so many attributes, I feel a little confused. Accustomed to the document format of swaggger, I wonder if there is a way to realize this requirement. Did you find it online, and then did it yourself. keyword Reflect one key ...

Exchange Group: 876618546           Exchange Group: 876618546 Direct boarding link Catalog I. Preparations   2. Start building 1. Install docke and set up boot-up 2. Draw the green dragon panel 3. Log on to the Qinglong panel 4. Pull Timer Task Script Warehouse 5. Apply Settings Configu ...

  Item Source System Target System Platform CENTOS7 - 64bit CENTOS7 - 64bit Database Oracle 11.2.0.4 Oracle 11.2.0.4 Character Set AL32UTF8 AL32UTF8 ORACLE_SID cd sz Listener Name/Port LISTENER/1521 LISTENER/1521 Goldengate User ogg ogg   1. Install OGG and create a directory (both sou ...

return and job management of SaltStack return of SaltStack component The return component can be understood as the SaltStack system stores or returns the data returned by Minion to other programs. It supports a variety of storage methods, such as MySQL, MongoDB, Redis, Memcache, etc. through return, we can record each operation of SaltSta ...

Classification of SQL classificationexplainData definition languageFor short, DDL(Data De "nition Language) is used to define database objects: database, table, column, etc.Data manipulation languageReferred to as DML (data management language), it is used to update the records of tables in the database.Data query languageDQL(Data Query L ...