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<>1. Basic knowledge
Software ： A collection of computer data and instructions organized in a specific order , Divided into system software and application software
<> systems software ：windows,mac os, linux,unix,android,ios,…
<> Application software ：word,ppt, Drawing board ,…
Human computer interaction mode ： Graphical interface vs Command line mode
<> application program = algorithm + data structure
<>2. The development of computer language
<> first generation ： machine language
<> Second generation ： assembly language
<> Third generation ： high-level language
> Process oriented ：C,Pascal,Fortran
> object-oriented ：Java,JS,Python,Scala,…
<>3.Java Language version overview
Specific details can be learned online . This is not very important , Just remember a few key times ,1996 Issued in JDK1.0,2004 Milestone version released in JDK1.5, Later, in order to reflect the importance of this version, it was renamed as JDK5.0,2014 Issued in JDK8.0, Yes JDK5.0 The most changed version since
<>4.Java Areas of language application
>Java Web development ： Background development
> Big data development ：
>Android application development ： Client development
<>5.Java Linguistic features
> Object oriented ：
Two elements ： class , object
Three characteristics ： encapsulation , inherit , polymorphic
> Robustness ：
1. remove C Pointers in languages
2. Automatic garbage collection mechanism -----> Memory overflow will still occur , Memory leak
> Cross platform ：write once,run anywhere： One time compilation , Run everywhere
Credit to ：JVM
Technology