Merge pull request #1195 from jasonrandrews/review

Add Java install guide and a Java page to the migration Learning Path

content/install-guides/java.md

@@ -0,0 +1,327 @@
+---
+title: Java
+author_primary: Jason Andrews
+minutes_to_complete: 15
+official_docs: https://docs.oracle.com/en/java/
+
+additional_search_terms:
+- linux
+- cloud
+
+multi_install: false
+multitool_install_part: false
+
+test_images:
+- ubuntu:latest
+test_maintenance: false
+
+tool_install: true
+weight: 1
+layout: installtoolsall
+---
+
+Java is a high-level, object-oriented programming language first released by Sun Microsystems in 1995.
+
+It is designed to have as few implementation dependencies as possible, making it a versatile and widely-used language.
+
+## Is Java available for Arm Linux?
+
+Yes, there are numerous ways to install Java on Arm Linux distributions. 
+
+Below are some of the common methods to install Java. This includes both the Java runtime environment (JRE), which is used to run Java applications and the Java development kit (JDK) which is used to create Java applications.
+
+Pick the one that works best for you.
+
+## Install Java using the Linux package manager
+
+For distributions using `apt` - including Debian and Ubuntu:
+
+```console
+sudo apt update
+sudo apt install default-jre -y
+sudo apt install default-jdk -y
+```
+
+For distributions using `dnf` - including Fedora and Red Hat:
+
+```console
+sudo dnf install java-latest-openjdk
+```
+
+For distributions using `pacman` - including Arch and Manjaro:
+
+```console
+sudo pacman -S jdk-openjdk  
+sudo pacman -S jre-openjdk  
+```
+
+## Install Java using Amazon Corretto
+
+Amazon Corretto is a no-cost distribution of the Open Java Development Kit (OpenJDK). It is maintained and supported by Amazon Web Services (AWS).
+
+You can install Corretto using `apt` with the commands:
+
+```console
+wget -O - https://apt.corretto.aws/corretto.key | sudo gpg --dearmor -o /usr/share/keyrings/corretto-keyring.gpg && \
+echo "deb [signed-by=/usr/share/keyrings/corretto-keyring.gpg] https://apt.corretto.aws stable main" | sudo tee /etc/apt/sources.list.d/corretto.list
+sudo apt-get update; sudo apt-get install -y java-21-amazon-corretto-jdk
+```
+
+More installation options for Corretto are available in the [Amazon Corretto 21 Guide for Linux](https://docs.aws.amazon.com/corretto/latest/corretto-21-ug/linux-info.html)
+
+## Install Java using Snap
+
+For Linux distributions with `snap` you can install Java using:
+
+```console
+sudo snap install openjdk
+```
+
+## Is there a way to install Java from the official website?
+
+You can download Java from the [Oracle website](https://www.oracle.com/java/technologies/javase-downloads.html) and install it manually. Look for the files with ARM64 in the description.
+
+Download a [tar.gz](https://download.oracle.com/java/22/latest/jdk-22_linux-aarch64_bin.tar.gz) file from the website. 
+
+Extract the contents of the file:
+
+```console
+tar xvf jdk-22_linux-aarch64_bin.tar.gz
+```
+
+Move the contents to a directory of your choice: 
+
+```console
+sudo mv jdk-22.0.2 /usr/local/
+```
+
+Set up environment variables to locate your installation:
+
+```console
+export JAVA_HOME=/usr/local/jdk-22.0.2
+export PATH=$JAVA_HOME/bin:$PATH
+```
+
+Add the environment variables to your `~/.bashrc` file to set them permanently.
+
+## Can I change the default Java version if multiple versions are installed?
+
+Yes, you can change the default version. For systems with `apt` use:
+
+```console
+sudo update-alternatives --config java
+```
+
+You will be given the option to select a new version. The options are depend on the software currently installed on your computer. 
+
+```output
+There are 3 choices for the alternative java (providing /usr/bin/java).
+
+  Selection    Path                                           Priority   Status
+------------------------------------------------------------
+* 0            /usr/lib/jvm/java-21-amazon-corretto/bin/java   12100004  auto mode
+  1            /usr/lib/jvm/java-17-openjdk-arm64/bin/java     1711      manual mode
+  2            /usr/lib/jvm/java-21-amazon-corretto/bin/java   12100004  manual mode
+  3            /usr/lib/jvm/java-21-openjdk-arm64/bin/java     2111      manual mode
+
+Press <enter> to keep the current choice[*], or type selection number:
+```
+
+For this case, if you select option 1, Java 17 becomes the default. 
+
+## How do I print the Java version?
+
+Print the version of the Java runtime:
+
+```console
+java -version
+```
+
+The output will be similar to:
+
+```output
+openjdk version "21.0.4" 2024-07-16
+OpenJDK Runtime Environment (build 21.0.4+7-Ubuntu-1ubuntu224.04)
+OpenJDK 64-Bit Server VM (build 21.0.4+7-Ubuntu-1ubuntu224.04, mixed mode, sharing)
+```
+
+Print the version of the Java compiler:
+
+```console
+javac -version
+```
+
+The output will be similar to:
+
+```output
+javac 21.0.4
+```
+
+## Which version of Java should I use for Arm Linux systems?
+
+It’s important to ensure that your version of Java is at least 11.0.9. There are large performance improvements starting from version 11.0.9. Since then, Java performance has steadily increased over time and newer versions will provide better performance.
+
+## Which flags are available for tuning the JVM?
+
+The Java virtual machine (JVM) includes a number of flags which are available to tune performance and aid in debugging. Some of the flags are general purpose and some are Arm architecture specific. 
+
+To print the final values of the flags after the JVM has been initialized run:
+
+```console
+java -XX:+PrintFlagsFinal -version
+```
+
+## Are there other tools commonly used in Java projects?
+
+There are a number of Java related tools you may want to install.
+
+### Apache Maven
+
+Apache Maven is a powerful build automation tool primarily used for Java projects. 
+
+It simplifies the build process by providing a uniform build system, dependency management, and project management capabilities.
+
+You can install it from the `apt` package manager:
+
+```console
+sudo apt-get install -y maven
+```
+
+Print the version:
+
+```console
+mvn -v
+```
+
+The output is similar to:
+
+```output
+Apache Maven 3.8.7
+Maven home: /usr/share/maven
+Java version: 22.0.2, vendor: Oracle Corporation, runtime: /usr/local/jdk-22.0.2
+Default locale: en, platform encoding: UTF-8
+OS name: "linux", version: "6.8.0-41-generic", arch: "aarch64", family: "unix"
+```
+
+### Gradle
+
+Gradle is another build automation tool that is widely used for Java projects. 
+
+It is designed to be highly customizable and flexible, making it suitable for a wide range of projects. 
+
+You can install it from the `apt` package manager:
+
+```console
+sudo apt install gradle -y
+```
+
+You can also install specific versions by downloading and extracting a zip file:
+
+```console
+wget https://services.gradle.org/distributions/gradle-8.10-bin.zip -O gradle-8.10-bin.zip
+unzip gradle-8.10-bin.zip
+sudo mv gradle-8.10 /opt/gradle
+sudo ln -s /opt/gradle/bin/gradle /usr/local/bin/gradle
+```
+
+Print the version:
+
+```console
+gradle -v
+```
+
+The output is similar to:
+
+```output
+Welcome to Gradle 8.10!
+
+Here are the highlights of this release:
+ - Support for Java 23
+ - Faster configuration cache
+ - Better configuration cache reports
+
+For more details see https://docs.gradle.org/8.10/release-notes.html
+
+
+------------------------------------------------------------
+Gradle 8.10
+------------------------------------------------------------
+
+Build time:    2024-08-14 11:07:45 UTC
+Revision:      fef2edbed8af1022cefaf44d4c0514c5f89d7b78
+
+Kotlin:        1.9.24
+Groovy:        3.0.22
+Ant:           Apache Ant(TM) version 1.10.14 compiled on August 16 2023
+Launcher JVM:  22.0.2 (Oracle Corporation 22.0.2+9-70)
+Daemon JVM:    /usr/local/jdk-22.0.2 (no JDK specified, using current Java home)
+OS:            Linux 6.8.0-41-generic aarch64
+```
+
+### Apache Ant
+
+Apache Ant is a Java-based build tool used to automate the build process for Java projects. It is similar to Make but is designed specifically for Java projects. 
+
+Ant uses XML to describe the build process and dependencies.
+
+You can install it from the `apt` package manager:
+
+```console
+sudo apt install ant -y
+```
+
+You can also install specific versions by downloading and extracting a zip file:
+
+```console
+wget https://downloads.apache.org/ant/binaries/apache-ant-1.10.13-bin.zip -O apache-ant-1.10.13-bin.zip
+unzip apache-ant-1.10.13-bin.zip
+sudo mv apache-ant-1.10.13 /opt/ant
+sudo ln -s /opt/ant/bin/ant /usr/local/bin/ant
+```
+
+Print the version:
+
+```console
+ant -version
+```
+
+The output is similar to:
+
+```output
+Apache Ant(TM) version 1.10.13 compiled on January 4 2023
+```
+
+### Apache JMeter
+
+JMeter is an open-source tool designed for performance and load testing Java applications. 
+
+You can install it using:
+
+```console
+wget https://downloads.apache.org/jmeter/binaries/apache-jmeter-5.6.3.tgz
+tar xzf apache-jmeter-5.6.3.tgz
+sudo mv apache-jmeter-5.6.3 /opt/jmeter
+sudo ln -s /opt/jmeter/bin/jmeter /usr/local/bin/jmeter
+```
+
+Print the version:
+
+```console
+jmeter --version
+```
+
+The output is similar to:
+
+```output
+Aug 27, 2024 9:01:58 PM java.util.prefs.FileSystemPreferences$1 run
+INFO: Created user preferences directory.
+    _    ____   _    ____ _   _ _____       _ __  __ _____ _____ _____ ____
+   / \  |  _ \ / \  / ___| | | | ____|     | |  \/  | ____|_   _| ____|  _ \
+  / _ \ | |_) / _ \| |   | |_| |  _|    _  | | |\/| |  _|   | | |  _| | |_) |
+ / ___ \|  __/ ___ \ |___|  _  | |___  | |_| | |  | | |___  | | | |___|  _ <
+/_/   \_\_| /_/   \_\____|_| |_|_____|  \___/|_|  |_|_____| |_| |_____|_| \_\ 5.6.3
+
+Copyright (c) 1999-2024 The Apache Software Foundation
+```
+
+You are ready to use Java on your Arm Linux system. 

content/learning-paths/servers-and-cloud-computing/migration/golang.md

@@ -2,7 +2,7 @@
 # User change
 title: "Migrating Go applications"
 
-weight: 4
+weight: 5
 
 layout: "learningpathall"
 

content/learning-paths/servers-and-cloud-computing/migration/isv.md

@@ -2,7 +2,7 @@
 # User change
 title: "List of software products supporting Arm"
 
-weight: 5
+weight: 6
 
 layout: "learningpathall"
 ---