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Environment setup

  • JRE (Java Runtime Environment): enables Java code execution, because Java is a cross-platform environment →\rightarrow 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