Environment setup
- JRE (Java Runtime Environment): enables Java code execution, because Java is a cross-platform environment we don't need native code, we need thing called byte codes
- JDK (Java Development Kit): provides tools required to create Java apps (licensed - Oracle Corporation, open source version - OpenJDK)
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Java Development Kit (JDK)
It is
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Installation
Install the Java SE (the standard edition JDK)
Steps:
- Download the latest JDK at jdk.java.net
- Setup
JAVA_HOME
variable - Update
PATH
variable - Verify correct installation
java --version
Windows
macOS
Download and unpack it into /Library/Java/JavaVirtualMachine/
and setting JAVA_HOME
and path variables.
Or using Homebrew
:
brew tap homebew/cask-versions # install Homebrew Cask
brew cask install java
Linux
/opt
Ubuntu:
apt update
apt install openjdk-13-jdk
update-alternatives --config java
Integrated Development Environment (IDE)
Native way
Use javac
and java
javac Hello.java # <- Java compiler takes the code and turn it into Java bytecode (create Hello.class)
java Hello # JVM runs the .class file
Other way is to use a popular Java IDE like:
- IntelliJ IDEA, JetBrains
- Eclipse, Eclipse Foundation
- NetBeans, Apache Foundation (before: Oracle)
IntelliJ
Use it!
Packing Java Application
Java applications are packaged into JAR (Java ARchive) files, which contains application classes and metadata.
We can create launch-able JAR file in many ways:
Native way
c
: create, v
: verbose, f
: filename, m
:
jar cvmf TC-MANIFEST.MF MyApplication.jar
Create TC-MANIFEST.MF
Main-Class: com.hahaha.Main
Run:
java -jar MyApplication.jar
Build tools
- Maven
- Gradle