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Rene.gabriel: /* Verificar a versão */

2024-09-11T23:32:23Z

Verificar a versão

Renefgj: /* Instalando o Java 17 */

2023-09-25T13:48:02Z

Instalando o Java 17

Renefgj em 13h47min de 25 de setembro de 2023

2023-09-25T13:47:27Z

Renefgj: /* Instalação para desenvolvimento */

2023-01-12T15:26:46Z

Instalação para desenvolvimento

Renefgj: /* Instalação para desenvolvimento */

2023-01-12T15:26:31Z

Instalação para desenvolvimento

Renefgj: /* Instalação padrão */

2023-01-12T15:25:01Z

Instalação padrão

Renefgj em 13h48min de 22 de julho de 2021

2021-07-22T13:48:57Z

Renefgj: Criou página com '

Introduction

Java and the JVM (Java's virtual machine) are required for many kinds of software, including To...'

2020-06-06T14:38:37Z

Criou página com '<h3 id="introduction">Introduction</h3> <p>Java and the JVM (Java's virtual machine) are required for many kinds of software, including <a href="http://tomcat.apache.org/">To...'

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<h3 id="introduction">Introduction</h3>

<p>Java and the JVM (Java's virtual machine) are required for many kinds of software, including <a href="http://tomcat.apache.org/">Tomcat</a>, <a href="https://www.eclipse.org/jetty/">Jetty</a>, <a href="https://javaee.github.io/glassfish/">Glassfish</a>, <a href="http://cassandra.apache.org/">Cassandra</a> and <a href="https://jenkins.io/">Jenkins</a>.</p>

<p>In this guide, you will install various versions of the Java Runtime Environment (JRE) and the Java Developer Kit (JDK) using <code>apt</code> . You'll install OpenJDK as well as official packages from Oracle. You'll then select the version you wish to use for your projects. When you're finished, you'll be able to use the JDK to develop software or use the Java Runtime to run software.</p>

<h2 id="prerequisites">Prerequisites</h2>

<p>To follow this tutorial, you will need:</p>

<ul>
<li>One Ubuntu 18.04 server set up by following the <a href="https://www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-18-04">the Ubuntu 18.04 initial server setup guide</a> tutorial, including a sudo non-root user and a firewall.</li>
</ul>

<h2 id="installing-the-default-jre-jdk">Installing the Default JRE/JDK</h2>

<p>The easiest option for installing Java is to use the version packaged with Ubuntu. By default, Ubuntu 18.04 includes Open JDK, which is an open-source variant of the JRE and JDK.</p>

<p>This package will install either OpenJDK 10 or 11.</p>

<ul>
<li>Prior to September 2018, this will install OpenJDK 10. </li>
<li>After September 2018, this will install OpenJDK 11.</li>
</ul>

<p>To install this version, first update the package index:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt update
</li></ul></code></pre>
<p>Next, check if Java is already installed:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">java -version
</li></ul></code></pre>
<p>If Java is not currently installed, you'll see the following output:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>Command 'java' not found, but can be installed with:

apt install default-jre
apt install openjdk-11-jre-headless
apt install openjdk-8-jre-headless
apt install openjdk-9-jre-headless
</code></pre>
<p>Execute the following command to install OpenJDK:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install default-jre
</li></ul></code></pre>
<p>This command will install the Java Runtime Environment (JRE). This will allow you to run almost all Java software. </p>

<p>Verify the installation with:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">java -version
</li></ul></code></pre>
<p>You'll see the following output:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>openjdk version "<span class="highlight">10.0.1" 2018-04-17</span>
OpenJDK Runtime Environment (build <span class="highlight">10.0.1+10</span>-Ubuntu-3ubuntu1)
OpenJDK 64-Bit Server VM (build <span class="highlight">10.0.1+10</span>-Ubuntu-3ubuntu1, mixed mode)
</code></pre>
<p>You may need the Java Development Kit (JDK) in addition to the JRE in order to compile and run some specific Java-based software. To install the JDK, execute the following command, which will also install the JRE:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install default-jdk
</li></ul></code></pre>
<p>Verify that the JDK is installed by checking the version of <code>javac</code>, the Java compiler:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">javac -version
</li></ul></code></pre>
<p>You'll see the following output:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>javac 10.0.1
</code></pre>
<p>Next, let's look at specifying which OpenJDK version we want to install.</p>

<h2 id="installing-specific-versions-of-openjdk">Installing Specific Versions of OpenJDK</h2>

<p>While you can install the default OpenJDK package, you can also install different versions of OpenJDK.</p>

<h3 id="openjdk-8">OpenJDK 8</h3>

<p>Java 8 is the current Long Term Support version and is still widely supported, though public maintenance ends in January 2019. To install OpenJDK 8, execute the following command:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install openjdk-8-jdk
</li></ul></code></pre>
<p>Verify that this is installed with</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">java -version
</li></ul></code></pre>
<p>You'll see output like this:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>openjdk version "<span class="highlight">1.8.0_162</span>"
OpenJDK Runtime Environment (build <span class="highlight">1.8.0_162-8u162-b12-1-b12</span>)
OpenJDK 64-Bit Server VM (build <span class="highlight">25.162-b12</span>, mixed mode)
</code></pre>
<p>It is also possible to install only the JRE, which you can do by executing <code>sudo apt install openjdk-8-jre</code>.</p>

<h3 id="openjdk-10-11">OpenJDK 10/11</h3>

<p>Ubuntu's repositories contain a package that will install either Java 10 or 11. Prior to September 2018, this package will install OpenJDK 10. Once Java 11 is released, this package will install Java 11. </p>

<p>To install OpenJDK 10/11, execute the following command:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install openjdk-11-jdk
</li></ul></code></pre>
<p>To install the JRE only, use the following command:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install openjdk-11-jre
</li></ul></code></pre>
<p>Next, let's look at how to install Oracle's official JDK and JRE.</p>

<h2 id="installing-the-oracle-jdk">Installing the Oracle JDK</h2>

<p>If you want to install the Oracle JDK, which is the official version distributed by Oracle, you'll need to add a new package repository for the version you'd like to use.</p>

<p>To install Java 8, which is the latest LTS version, first add its package repository:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo add-apt-repository ppa:webupd8team/java
</li></ul></code></pre>
<p>When you add the repository, you'll see a message like this:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="output">output</div> Oracle Java (JDK) Installer (automatically downloads and installs Oracle JDK8). There are no actual Jav
a files in this PPA.

Important -> Why Oracle Java 7 And 6 Installers No Longer Work: http://www.webupd8.org/2017/06/why-oracl
e-java-7-and-6-installers-no.html

Update: Oracle Java 9 has reached end of life: http://www.oracle.com/technetwork/java/javase/downloads/j
dk9-downloads-3848520.html

The PPA supports Ubuntu 18.04, 17.10, 16.04, 14.04 and 12.04.

More info (and Ubuntu installation instructions):
- for Oracle Java 8: http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html

Debian installation instructions:
- Oracle Java 8: http://www.webupd8.org/2014/03/how-to-install-oracle-java-8-in-debian.html

For Oracle Java 10, see a different PPA: https://www.linuxuprising.com/2018/04/install-oracle-java-10-in-ubuntu-or.html

More info: https://launchpad.net/~webupd8team/+archive/ubuntu/java
Press [ENTER] to continue or Ctrl-c to cancel adding it.
</code></pre>
<p>Press <code>ENTER</code> to continue. Then update your package list:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt update
</li></ul></code></pre>
<p>Once the package list updates, install Java 8:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo apt install oracle-java8-installer
</li></ul></code></pre>
<p>Your system will download the JDK from Oracle and ask you to accept the license agreement. Accept the agreement and the JDK will install.</p>

<p>Now let's look at how to select which version of Java you want to use.</p>

<h2 id="managing-java">Managing Java</h2>

<p>You can have multiple Java installations on one server. You can configure which version is the default for use on the command line by using the <code>update-alternatives</code> command.</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo update-alternatives --config java
</li></ul></code></pre>
<p>This is what the output would look like if you've installed all versions of Java in this tutorial:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>There are 3 choices for the alternative java (providing /usr/bin/java).

Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 auto mode
1 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode
3 /usr/lib/jvm/java-8-oracle/jre/bin/java 1081 manual mode
</code></pre>
<p>Choose the number associated with the Java version to use it as the default, or press <code>ENTER</code> to leave the current settings in place.</p>

<p>You can do this for other Java commands, such as the compiler (<code>javac</code>):</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo update-alternatives --config <span class="highlight">javac</span>
</li></ul></code></pre>
<p>Other commands for which this command can be run include, but are not limited to: <code>keytool</code>, <code>javadoc</code> and <code>jarsigner</code>.</p>

<h2 id="setting-the-java_home-environment-variable">Setting the <code>JAVA_HOME</code> Environment Variable</h2>

<p>Many programs written using Java use the <code>JAVA_HOME</code> environment variable to determine the Java installation location. </p>

<p>To set this environment variable, first determine where Java is installed. Use the <code>update-alternatives</code> command:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo update-alternatives --config java
</li></ul></code></pre>
<p>This command shows each installation of Java along with its installation path:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div>There are 3 choices for the alternative java (providing /usr/bin/java).

Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 auto mode
1 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode
3 /usr/lib/jvm/java-8-oracle/jre/bin/java 1081 manual mode

Press <enter> to keep the current choice[*], or type selection number:
</code></pre>
<p>In this case the installation paths are as follows:</p>

<ol>
<li>OpenJDK 11 is located at <code>/usr/lib/jvm/java-11-openjdk-amd64/bin/java.</code></li>
<li>OpenJDK 8 is located at <code>/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java</code>.</li>
<li>Oracle Java 8 is located at <code>/usr/lib/jvm/java-8-oracle/jre/bin/java</code>.</li>
</ol>

<p>Copy the path from your preferred installation. Then open <code>/etc/environment</code> using <code>nano</code> or your favorite text editor:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo nano /etc/environment
</li></ul></code></pre>
<p>At the end of this file, add the following line, making sure to replace the highlighted path with your own copied path:</p>
<div class="code-label " title="/etc/environment">/etc/environment</div><pre class="code-pre "><code langs="">JAVA_HOME="<span class="highlight">/usr/lib/jvm/java-11-openjdk-amd64/bin/</span>"
</code></pre>
<p>Modifying this file will set the <code>JAVA_HOME</code> path for all users on your system.</p>

<p>Save the file and exit the editor.</p>

<p>Now reload this file to apply the changes to your current session:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">source /etc/environment
</li></ul></code></pre>
<p>Verify that the environment variable is set:</p>
<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">echo $JAVA_HOME
</li></ul></code></pre>
<p>You'll see the path you just set:</p>
<pre class="code-pre "><code langs=""><div class="secondary-code-label " title="Output">Output</div><span class="highlight">/usr/lib/jvm/java-11-openjdk-amd64/bin/</span>
</code></pre>
<p>Other users will need to execute the command <code>source /etc/environment</code> or log out and log back in to apply this setting.</p>

<h2 id="conclusion">Conclusion</h2>

<p>In this tutorial you installed multiple versions of Java and learned how to manage them. You can now install software which runs on Java, such as Tomcat, Jetty, Glassfish, Cassandra or Jenkins.</p>

</div>
</div>

← Edição anterior		Edição das 13h48min de 25 de setembro de 2023
Linha 4:		Linha 4:
	apt install openjdk-17-jdk openjdk-17-jre		apt install openjdk-17-jdk openjdk-17-jre

		+	===Ver versão do Java==
		+	java -version

	== Instalação padrão ==		== Instalação padrão ==

← Edição anterior		Edição das 13h47min de 25 de setembro de 2023
Linha 1:		Linha 1:
	= Introdução =		= Introdução =
		+	== Instalando o Java 17 ==
		+	===Ubuntu===
		+	apt install openjdk-17-jdk openjdk-17-jre
		+

	== Instalação padrão ==		== Instalação padrão ==

@@ Linha 6: / Linha 6: @@
 == Instalação para desenvolvimento ==
   apt install default-jdk
 == Verificar a versão ==

@@ Linha 6: / Linha 6: @@
 == Instalação para desenvolvimento ==
   apt install default-jdk
 == Verificar a versão ==

@@ Linha 2: / Linha 2: @@
 == Instalação padrão ==
-  pt install default-jre
+  apt install default-jre
 == Instalação para desenvolvimento ==

@@ Linha 167: / Linha 167: @@
 <p>You can do this for other Java commands, such as the compiler (<code>javac</code>):</p>
-<pre class="code-pre command"><code langs=""><ul class="prefixed"><li class="line" prefix="$">sudo update-alternatives --config <span class="highlight">javac</span>
+ sudo update-alternatives --config
-</li></ul></code></pre>
+ javac
 <p>Other commands for which this command can be run include, but are not limited to: <code>keytool</code>, <code>javadoc</code> and <code>jarsigner</code>.</p>

← Edição anterior		Edição das 13h48min de 22 de julho de 2021
Linha 1:		Linha 1:
−	~~<h3 id~~=~~"introduction">Introduction</h3>~~	+	= Introdução =
		+
		+	== Instalação padrão ==
		+	pt install default-jre
		+
		+	== Instalação para desenvolvimento ==
		+	apt install default-jdk
		+
		+	== Verificar a versão ==
		+	java -v
		+

	<p>Java and the JVM (Java's virtual machine) are required for many kinds of software, including <a href="http://tomcat.apache.org/">Tomcat</a>, <a href="https://www.eclipse.org/jetty/">Jetty</a>, <a href="https://javaee.github.io/glassfish/">Glassfish</a>, <a href="http://cassandra.apache.org/">Cassandra</a> and <a href="https://jenkins.io/">Jenkins</a>.</p>		<p>Java and the JVM (Java's virtual machine) are required for many kinds of software, including <a href="http://tomcat.apache.org/">Tomcat</a>, <a href="https://www.eclipse.org/jetty/">Jetty</a>, <a href="https://javaee.github.io/glassfish/">Glassfish</a>, <a href="http://cassandra.apache.org/">Cassandra</a> and <a href="https://jenkins.io/">Jenkins</a>.</p>