.gitignore

+# Created by https://www.gitignore.io/api/java,linux,macos,gradle,windows,eclipse,intellij
+# Edit at https://www.gitignore.io/?templates=java,linux,macos,gradle,windows,eclipse,intellij
+
+### Eclipse ###
+.metadata
+bin/
+tmp/
+*.tmp
+*.bak
+*.swp
+*~.nib
+local.properties
+.settings/
+.loadpath
+.recommenders
+
+# External tool builders
+.externalToolBuilders/
+
+# Locally stored "Eclipse launch configurations"
+*.launch
+
+# PyDev specific (Python IDE for Eclipse)
+*.pydevproject
+
+# CDT-specific (C/C++ Development Tooling)
+.cproject
+
+# CDT- autotools
+.autotools
+
+# Java annotation processor (APT)
+.factorypath
+
+# PDT-specific (PHP Development Tools)
+.buildpath
+
+# sbteclipse plugin
+.target
+
+# Tern plugin
+.tern-project
+
+# TeXlipse plugin
+.texlipse
+
+# STS (Spring Tool Suite)
+.springBeans
+
+# Code Recommenders
+.recommenders/
+
+# Annotation Processing
+.apt_generated/
+
+# Scala IDE specific (Scala & Java development for Eclipse)
+.cache-main
+.scala_dependencies
+.worksheet
+
+### Eclipse Patch ###
+# Eclipse Core
+.project
+
+# JDT-specific (Eclipse Java Development Tools)
+.classpath
+
+# Annotation Processing
+.apt_generated
+
+.sts4-cache/
+
+### Intellij ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Intellij Patch ###
+# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+
+# *.iml
+# modules.xml
+# .idea/misc.xml
+# *.ipr
+
+# Sonarlint plugin
+.idea/sonarlint
+
+### Java ###
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+# *.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+### Linux ###
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+### macOS ###
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Windows ###
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+### Maven ###
+target/
+
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+### Gradle Patch ###
+**/build/
+
+# End of https://www.gitignore.io/api/java,linux,macos,gradle,windows,eclipse,intellij

.gitlab-ci.yml

-image: gradle:jdk12
-
-before_script:
-  - export GRADLE_USER_HOME=`pwd`/lectures/.gradle
-
-cache:
-  paths:
-    - lectures/.gradle/wrapper
-    - lectures/.gradle/caches
-    - lectures/build
+image: maven:3.9.9-eclipse-temurin-17
 
 build:
   stage: build
   script:
-    - cd lectures
-    - ./gradlew build
+    - mvn "-Dci=gitlab" process-resources
+
+pages:
+  script:
+    - mvn "-Dci=gitlab" process-resources
+    - cp -r target/docs/* public
+#  only:
+#    - master
   artifacts:
     paths:
-    - lectures/build/docs
-    expire_in: 1 week
+      - public

.gitpod.Dockerfile

+FROM gitpod/workspace-full-vnc
+                    
+USER gitpod
+
+# Install custom tools, runtime, etc. using apt-get
+# For example, the command below would install "bastet" - a command line tetris clone:
+#
+# RUN sudo apt-get -q update && #     sudo apt-get install -yq bastet && #     sudo rm -rf /var/lib/apt/lists/*
+#
+# More information: https://www.gitpod.io/docs/config-docker/

.gitpod.yml

+tasks:
+  - init: echo "Replace me with a build script for the project."
+    command: echo "Replace me with something that should run on every start, or just
+      remove me entirely."
+image:
+  file: .gitpod.Dockerfile

.mailmap

+Hallvard Trætteberg <hal@ntnu.no> Hallvard Trætteberg <hal@ntnu.no>
+Hallvard Trætteberg <hal@ntnu.no> Hallvard Traetteberg <hal@ntnu.no>
+Adrian Stoica <george.a.stoica@ntnu.no> Adrian Stoica <george.a.stoica@ntnu.no>  
+Adrian Stoica <george.a.stoica@ntnu.no> georgeas <george.a.stoica@ntnu.no>
+Adrian Stoica <george.a.stoica@ntnu.no> George Adrian Stoica <george.a.stoica@ntnu.no>
+Pål-Edward Larsen <paaledwl@stud.ntnu.no> Pål-Edward Larsen <paaledwl@stud.ntnu.no>
+Pål-Edward Larsen <paaledwl@stud.ntnu.no> paaledwl <paaledwl@stud.ntnu.no>

.vscode/tasks.json

+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "gradle run",
+            "type": "shell",
+            "command": "gradle",
+            "args": ["run"]
+        },
+        {
+            "label": "gradle version",
+            "type": "shell",
+            "command": "gradle",
+            "args": ["--version"]
+        },
+        {
+            "label": "java -version",
+            "type": "shell",
+            "command": "java",
+            "args": ["-version"]
+        },
+        {
+            "label": "sdk use java 12.0.2-open",
+            "type": "shell",
+            "command": "sdk",
+            "args": ["use", "java", "12.0.2-open"]
+        }
+    ]
+}
\ No newline at end of file

How To.md

+## Installation
+### Install Java
+
+#### [Guide for installing Java Development Kit](https://gitlab.stud.idi.ntnu.no/it1901/course-material/blob/master/howto/get-java.md "Installing Java")
+
+
+#### Download links
+
+* http://jdk.java.net 
+* https://www.oracle.com/technetwork/java/javase/downloads/index.html
+
+
+#### How and why to uninstall older versions of Java
+https://www.java.com/en/download/faq/remove_olderversions.xml
+
+### Install Git
+#### Download link
+https://git-scm.com/book/en/v2/Getting-Started-Installing-Git
+
+#### For Windows we recommend Git for Windows
+https://gitforwindows.org/
+
+### Install Eclipse or Intellij
+#### Intellij download link (download the free community edition)
+https://www.jetbrains.com/idea/download/#section=mac
+
+#### Eclipse for Java download link 
+https://www.eclipse.org/downloads/packages/release/2019-06/r/eclipse-ide-java-developers
+
+## Update the local project credentials to match your Gitlab user.
+1) Open the terminal window and go to your Gitlab project
+2) Update local user email with 'git config --local user.email YOUR_NTNU_USERNAME@stud.ntnu.no'
+3) Update local user password with 'git config --local user.password YOUR_NTNU_PASSWORD'
+4) Update local user username with 'git config --local user.name YOUR_NTNU_USERNAME'
+
+## How to clone video 
+VIDEO: https://vimeo.com/355521976

README.md

+[![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.idi.ntnu.no/#https://gitlab.stud.idi.ntnu.no/it1901/course-material) 
+
 # course-material
 
 Course material for IT1901
\ No newline at end of file

antipatterns/.gitignore

+target/
+.classpath
+.project

antipatterns/pom.xml

+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  	<modelVersion>4.0.0</modelVersion>
+  	<groupId>it1901</groupId>
+  	<artifactId>antipatterns</artifactId>
+  	<version>0.0.1-SNAPSHOT</version>
+  
+	<dependencies>
+
+		<!-- Test with JUnit5 -->
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-api</artifactId>
+			<version>5.4.2</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-engine</artifactId>
+			<version>5.4.2</version>
+			<scope>test</scope>
+		</dependency>		
+	</dependencies>
+
+	<build>
+		<plugins>
+			<!-- Compiling code -->
+			<plugin>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.8.1</version>
+				<configuration>
+					<encoding>UTF-8</encoding>
+					<release>13</release>
+				</configuration>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+                <version>3.0.0-M5</version>
+                <!-- 
+                <configuration>
+                    <argLine>${argLine} dash dash add-exports javafx.graphics/com.sun.javafx.application=ALL-UNNAMED</argLine>
+                </configuration>
+                 -->
+			</plugin>
+		</plugins>
+  	</build>
+</project>
\ No newline at end of file

antipatterns/src/main/java/antipatterns/DataClassWithEffectivelyFinalFields.java

+package antipatterns;
+
+public class DataClassWithEffectivelyFinalFields {
+
+  private final String name; // should be final
+  private final int number; // should be final
+
+  public DataClassWithEffectivelyFinalFields(final String name, final int number) {
+    this.name = name;
+    this.number = number;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public int getNumber() {
+    return number;
+  }
+}

antipatterns/src/main/java/antipatterns/DataClassWithLittleLogic.java

+package antipatterns;
+
+// ok, but see the test
+public class DataClassWithLittleLogic {
+
+  private String name;
+  private int number;
+
+  public DataClassWithLittleLogic(final String name, final int number) {
+    this.name = name;
+    this.number = number;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("[DataClassWithLittleLogic name=%s number=%s]", name, number);
+  }
+
+  public DataClassWithLittleLogic() {
+  }
+
+  public String getName() {
+    return name;
+  }
+  public void setName(final String name) {
+    this.name = name;
+  }
+
+  public int getNumber() {
+    return number;
+  }
+  public void setNumber(final int number) {
+    this.number = number;
+  }
+}

antipatterns/src/main/java/antipatterns/DataClassWithValidation.java

+package antipatterns;
+
+// see DataClassWithValidationTest
+public class DataClassWithValidation {
+
+  private String name;
+
+  public DataClassWithValidation(final String name) {
+    // should use setName to ensure validation logic is run
+    this.name = name;
+  }
+
+  public DataClassWithValidation() {
+  }
+
+  public String getName() {
+    return name;
+  }
+  public void setName(final String name) {
+    if (name.startsWith(" ")) {
+      // should rather use trim() or strip() and check the length
+      throw new IllegalArgumentException("Name cannot begin with blank");
+    }
+    this.name = name;
+  }
+}

antipatterns/src/main/java/antipatterns/NonEncapsulatedList.java

+package antipatterns;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+public class NonEncapsulatedList implements Iterable<String> {
+
+  private final Collection<String> names;
+
+  public NonEncapsulatedList(final Collection<String> names) {
+    this.names = names;
+  }
+
+  public Collection<String> getNames() {
+    return names;
+  }
+
+  public Iterator<String> iterator() {
+    return names.iterator();
+  }
+}

antipatterns/src/test/java/antipatterns/DataClassWithLittleLogicTest.java

+package antipatterns;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class DataClassWithLittleLogicTest {
+
+  private DataClassWithLittleLogic instance1, instance2;
+
+  @BeforeEach
+  public void setup() {
+    instance1 = new DataClassWithLittleLogic();
+    instance2 = new DataClassWithLittleLogic("High", 5);
+  }
+
+  @Test
+  public void testConstructor() {
+    Assertions.assertEquals("High", instance2.getName());
+  }
+
+  @Test
+  public void testToString() {
+    Assertions.assertEquals("[DataClassWithLittleLogic name=High number=5]", instance2.toString());
+  }
+
+  @Test
+  public void testSetName() {
+    instance1.setName("Low");
+    Assertions.assertEquals("Low", instance1.getName());
+  }
+}

antipatterns/src/test/java/antipatterns/DataClassWithValidationTest.java

+package antipatterns;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class DataClassWithValidationTest {
+
+  @Test
+  public void testSetName() {
+    try {
+      new DataClassWithValidation(" name starting with blank");
+      Assertions.fail("Should throw IllegalArgumentException");
+    } catch (final IllegalArgumentException iae) {
+    } catch (final Exception iae) {
+      Assertions.fail("Should throw IllegalArgumentException");
+    }
+
+    try {
+      new DataClassWithValidation("ok name");
+    } catch (final Exception iae) {
+      Assertions.fail();
+    }
+  }
+
+  @Test
+  public void testBetterSetName_invalidName() {
+    Assertions.assertThrows(IllegalArgumentException.class, () -> new DataClassWithValidation(" name starting with blank"));
+  }
+
+  @Test
+  public void testBetterSetName_validName() {
+    new DataClassWithValidation("ok name");
+  }
+}

simpleexample/gradle/wrapper/gradle-wrapper.properties → gradle/wrapper/gradle-wrapper.properties

 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

howto/get-java.md

+# Setting up Java
+
+![](logos/java.png)
+
+To be able to develop in Java one requires a JDK - Java Development Kit. You have to download and properly set up java
+For IT1901 either JDK 11 or 12 will do just fine.
+
+Installing manually the jdk has the following steps no matter what operating system you are using:
+
+* download the archive containing the desired release
+* extract it
+* move it to a meaningful location (depends on the os what is a good location)
+* set up environment variables for `JAVA_HOME` and `PATH`
+* apply changes if necessary
+
+Note: The examples shown here use filenames as they were for jdk 12.0.2 at the moment of redacting the document. Adjust the filenames and the paths as needed. Depending on your OS version or flavour you might have different text editors and you might need to adjust for that as well.  
+
+## Install java
+
+If there is no Java Development Kit installed or the version is not what you need (we recommend version 11 or 12) then proceed to download JDK and install it.
+
+### Windows
+
+#### Check if there is any java installed
+
+In a command line window type: 
+
+``` batch
+java -version
+```
+![](images/04%20-%20check%20for%20java%20windows.png)
+
+#### Extract downloaded binary
+
+After the download finishes you have in the destination folder the `.zip` file with a name like this `openjdk-12.0.2_windows-x64_bin.zip`. Right click it and extract the contents.
+
+![](images/05%20-%20extract%20openjdk%20windows.png)
+
+Copy the extracted folder in a meaningful location on your hard drive like for example in `C:\jdks` 
+
+![](images/06%20-%20move%20the%20jdk%20folder%20to%20c-jdks%20folder.png)
+
+
+#### Set up the environment variables    
+
+To properly set up Java on your machine you need to set couple environment variables. To do that you need to open "Environment variables" dialog box.
+There are several ways to get to that dialog box.
+
+Right click "This PC" and select "Properties" 
+
+![](images/07%20-%20open%20pc%20properties.png)
+
+You should see a window like the one below. Choose "Advanced System Settings" option in the top left side.
+
+![](images/08%20-%20pc%20properties%20window.png)
+
+A new window will open showing "System properties"
+
+![](images/09%20-%20system%20properties.png)
+
+Open "Environment Variables"
+
+If the JDK should be available for all users than make the environment variable changes at system level otherwise do them at user level.
+
+Check if there is already a `JAVA_HOME` environment variable. If it is change the value to the path to your JDK (`C:\jdks\jdk-12.0.2`)
+
+![](images/10%20-%20env%20java%20home.png)
+
+Next we need to add the `bin` folder within the JDK folder to the `PATH` environment variable so that the java commands are accessible from the command prompt
+
+![](images/11%20-%20env%20path.png)
+
+Finally we can check if java is now running as expected
+
+![](images/12%20-%20java%20check%20ok.png)
+
+##### Notes
+
+* You can check the values of environment variables from command prompt issuing commands such as `SET JAVA_HOME` or `SET PATH`
+* You can get to the environment variable dialog by other means
+	- search "env" in the windows start menu
+	- open System from the Control Panel and then "Environment Variables" 
+
+
+### Linux
+
+#### Check if there is any java installed
+
+Open a terminal window and type
+
+``` bash
+java -version
+```
+
+![](images/linux03_check_false.png)
+
+
+#### Extract downloaded binary
+
+After the download finishes you have in the destination folder the `.tar.gz` file with a name like this `openjdk-12.0.2_linux-x64_bin.tar.gz` . 
+
+Extract the files and place them in the desired location with the following commands
+
+
+``` bash
+tar zxvf openjdk-12.0.2_linux-x64_bin.tar.gz
+sudo mkdir /usr/lib/jvm
+sudo mv jdk-12.0.2 /usr/lib/jvm/
+```
+
+![](images/linux02_extract.png)
+
+![](images/linux04_move.png)
+
+
+#### Set up the environment variables 
+
+create a shell script in /etc/profile.d
+
+``` bash
+sudo nano /etc/profile.d/jdk.sh
+```
+
+![](images/linux05_env01.png)
+
+
+add the following lines inside the file and save and close
+
+``` bash
+export JAVA_HOME=/usr/lib/jvm/jdk-12.0.2
+export PATH=$PATH:$JAVA_HOME/bin
+
+```
+
+![](images/linux06_env02.png)
+
+apply changes
+
+logout and log back in or run the script you have just created
+
+``` bash
+bash /etc/profile.d/jdk.sh
+```
+
+
+check if everything is in order
+
+``` bash
+echo $JAVA_HOME
+java -version
+```
+
+![](images/linux07_check_true.png)
+
+### MacOs
+
+#### Check if there is any java installed
+
+Open a terminal window and type
+
+``` bash
+java -version
+```
+
+![](images/mac_02_check_false.png)
+
+
+#### Extract downloaded binary
+
+After the download finishes you have in the destination folder the `.tar.gz` file with a name like this `openjdk-12.0.2_osx-x64_bin.tar.gz`.
+
+Extract the files using the following command
+
+``` bash
+tar xf openjdk-12.0.2_osx-x64_bin.tar.gz
+```
+
+![](images/mac_03_extract.png)
+
+
+Move the extracted to the folder  `/Library/Java/JavaVirtualMachines/`
+You will need to execute the move with super user privileges in order to put the files in the system folder
+ 
+``` bash
+sudo mv jdk-12.0.2.jdk /Library/Java/JavaVirtualMachines/
+```
+
+![](images/mac_04_move.png)
+
+
+#### Set up the environment variables 
+
+To set up the environment variable `JAVA_HOME` we will need to edit the `.bash_profile` file in the home directory.
+
+If the file mentioned does not exist we can create it with the following command:
+
+``` bash
+touch ~/.bash_profile
+```
+
+![](images/mac_05_env01.png)
+
+
+We need to export the `JAVA_HOME` variable so we edit the file using
+
+``` bash
+edit ~/.bash_profile
+```
+or 
+
+``` bash
+nano ~/.bash_profile
+```
+
+![](images/mac_06_env02.png)
+
+
+we add the following line
+
+`export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-12.0.2.jdk/Contents/Home"`
+
+![](images/mac_08_env03.png)
+
+
+finally we save the changes and close the file. To apply the changes we need to run the following command
+
+``` bash
+source ~/.bash_profile
+```
+
+![](images/mac_07_apply_env.png)
+
+
+check if everything is in order
+
+![](images/mac_09_check_true.png)
+
+## Using sdkman
+
+sdkman is a tool that allows you to manage development kits including JDK. It is possible to run it on Linux and Mac without additional software. On windows one can use it after installing Git Bash and MinGW.
+Refer to the https://sdkman.io webpage for more info and instructions 
+
+### Installation on supported systems - open a terminal window and enter:
+
+``` bash
+curl -s "https://get.sdkman.io" | bash
+```
+
+Follow the instructions on-screen to complete installation.
+
+Apply changes by entering:
+
+``` bash
+source "$HOME/.sdkman/bin/sdkman-init.sh"
+```
+
+check the version using the command
+
+``` bash
+sdk version
+```
+
+If the tool is now properly installed the result of the previous command will be:
+
+``` bash
+ sdkman 5.x.x
+```
+
+
+### Typical usage
+
+After installation you will typically use commands like 
+
+``` bash
+sdk list java
+```
+list the available versions
+
+``` bash
+sdk install java
+```
+install latest java, add version number to install specific java
+
+``` bash
+sdk use java 12.0.2
+```
+use the java development kit with version 12.0.2
+
+
+See more commands on the sdkman.io site 
+
+
+
+## Download Java
+
+
+###  Open-source reference implementation (GNU GPL License, provided by Oracle)
+
+* 1. go to http://jdk.java.net
+
+![](images/01%20-%20jdk.java.net%20-%20home.png)
+
+* 2. select the general available build (currently 12)
+
+![](images/02%20-%20jdk.java.net%20-%20latest%20ga.png)
+
+* 3. download the binary corresponding to your operating system
+
+
+### Get binaries from Oracle site (Oracle license)
+
+1. go to https://www.oracle.com/technetwork/java/javase/downloads/index.html
+2. sign in (if you do not have an account you will need to create one in order to be allowed to download)
+3. select the latest (currently 12)
+4. download the binary corresponding to your operating system
+
+There are more choices for downloads. Typically a .zip or .tar.gz would imply manual setup while the .exe, .deb, .rpm, .dmg will provide some sort of installer support.  
+
+For the .zip or .tar.gz files you need to follow the procedure from above.
+.exe (windows) - run and follow the installer prompts
+.dmg (mac) - run and follow the installer prompts
+.deb (linux) - package format used in Debian and Ubuntu linux distributions
+
+```bash
+sudo dpkg -i ~/Downloads/jdk-12.0.2_linux-x64_bin.deb
+```
+
+alternative way to install .deb packages is with apt
+
+```bash
+sudo apt install ~/Downloads/jdk-12.0.2_linux-x64_bin.deb
+```
+In Ubuntu you can also double click the package and it will open in Software Center where there is an option to install it.
+
+.rpm (linux) - package format commonly used in Redhat and Mandrake linux distributions 
+
+``` bash
+rpm -ivh ~/Downloads/jdk-12.0.2_linux-x64_bin.rpm
+```