= JDK on Fedora

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[[abstract]]
Abstract
~~~~~~~~

This page provides information about *JDK* installations on Fedora. (See
also https://fedoraproject.org/wiki/Java[Java].)

This page will discuss mainly about Open JDK and Oracle JDK, how to
install them, test and configure them on Fedora.

[[what-is-jdk]]
What is JDK
~~~~~~~~~~~

JDK or Java Development Kit is an implementation of Java Environment,
Standard Edition and is required for Java development purposes.

[[openjdk-and-project-icedtea]]
OpenJDK and project IcedTea
~~~~~~~~~~~~~~~~~~~~~~~~~~~

OpenJDK (Open Java Development Kit) is a free and open source
implementation of the Java Platform, Standard Edition (Java SE). It is
the result of an effort Sun Microsystems began in 2006. The
implementation is licensed under the GNU General Public License (GNU
GPL) with a linking exception. Were it not for the GPL linking
exception, components that linked to the Java class library would be
subject to the terms of the GPL license. OpenJDK is the official Java SE
7 reference implementation. Fedora has shipped OpenJDK as default JRE
implementation. It's based on Sun Microsystem's/Oracle's
http://en.wikipedia.org/wiki/JavaOne[JavaOne] open source release and
complemented by Red Hat's http://en.wikipedia.org/wiki/IcedTea[IcedTea]
project that implements the missing third party components that
Sun/Oracle could not release under free License.

About the installation, see
https://developer.fedoraproject.org/tech/languages/java/java-installation.html[Developer.FedoraProject.Org/Java].

OpenJDK's *java.library.path*, shared librarary paths for i386 are:

....
/usr/lib
/usr/lib/jvm/java-1.?.0-openjdk-1.6.0.0.x86_64/jre/lib/
....

and for x86_64:

....
/usr/lib64
/usr/lib/jvm/java-1.?.0-openjdk-1.6.0.0.x86_64/jre/lib/amd64/
....

The JDK has as its primary components a collection of programming tools,
including:

[[jdk-components]]
JDK components
~~~~~~~~~~~~~~

appletviewer – this tool can be used to run and debug Java applets
without a web browser +
apt – the annotation-processing tool +
extcheck – a utility which can detect JAR-file conflicts +
idlj – the IDL-to-Java compiler. This utility generates Java bindings
from a given Java IDL file. +
jabswitch – the Java Access Bridge. Exposes assistive technologies on
Microsoft Windows systems. +
java – the loader for Java applications. This tool is an interpreter and
can interpret the class files generated by the javac compiler. Now a
single launcher is used for both development and deployment. The old
deployment launcher, jre, no longer comes with Sun JDK, and instead it
has been replaced by this new java loader. +
javac – the Java compiler, which converts source code into Java
bytecode +
javadoc – the documentation generator, which automatically generates
documentation from source code comments +
jar – the archiver, which packages related class libraries into a single
JAR file. This tool also helps manage JAR files. +
javafxpackager – tool to package and sign JavaFX applications +
jarsigner – the jar signing and verification tool +
javah – the C header and stub generator, used to write native methods +
javap – the class file disassembler +
javaws – the Java Web Start launcher for JNLP applications +
JConsole – Java Monitoring and Management Console +
jdb – the debugger +
jhat – Java Heap Analysis Tool (experimental) +
jinfo – This utility gets configuration information from a running Java
process or crash dump. (experimental) +
jmap – This utility outputs the memory map for Java and can print shared
object memory maps or heap memory details of a given process or core
dump. (experimental) +
jmc – Java Mission Control +
jps – Java Virtual Machine Process Status Tool lists the instrumented
HotSpot Java Virtual Machines (JVMs) on the target system.
(experimental) +
jrunscript – Java command-line script shell. +
jstack – utility which prints Java stack traces of Java threads
(experimental) +
jstat – Java Virtual Machine statistics monitoring tool (experimental) +
jstatd – jstat daemon (experimental) +
keytool – tool for manipulating the keystore +
pack200 – JAR compression tool +
policytool – the policy creation and management tool, which can
determine policy for a Java runtime, specifying which permissions are
available for code from various sources VisualVM – visual tool
integrating several command-line JDK tools and lightweight clarification
needed] performance and memory profiling capabilities +
wsimport – generates portable JAX-WS artifacts for invoking a web
service. +
xjc – Part of the Java API for XML Binding (JAXB) API. It accepts an XML
schema and generates Java classes. +
Experimental tools may not be available in future versions of the JDK.

The JDK also comes with a complete Java Runtime Environment, usually
called a private runtime, due to the fact that it is separated from the
"regular" JRE and has extra contents. It consists of a Java Virtual
Machine and all of the class libraries present in the production
environment, as well as additional libraries only useful to developers,
such as the internationalization libraries and the IDL libraries.

Copies of the JDK also include a wide selection of example programs
demonstrating the use of almost all portions of the Java API. OpenJDK
package name on Fedora is _java-1.?.0-openjdk_.

[[oracle-jdk]]
Oracle JDK
~~~~~~~~~~

Oracle provides JDK (Java Development Kit) for Java Developers. It
includes a complete JRE plus tools for developing, debugging, and
monitoring Java applications.

[[installing-oracle-jdk-on-fedora]]
Installing Oracle JDK on Fedora
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

\1. Download the Oracle Java JDK
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html[here] +
Note: download appropriate file, for example if your system is x64
Fedora the download file is named like this: jdk-8u45-linux-x64.tar.gz +
2. Create a folder named java in /usr/local/by this command:

....
sudo mkdir -p /usr/local/java
....

folder is created in root/usr/local/java +
3. Copy the Downloaded file in the directory /usr/local/java. To do
this, cd into directory where downloaded file is located and use this
command for copying that file to /usr/local/java/:

....
sudo cp -r jdk-8u40-linux-x64.tar.gz /usr/local/java
....

\4. CD into /usr/local/java/ directory and extract that copied file by
using this command:

....
sudo tar xvzf jdk-8u45-linux-x64.tar.gz
....

\5. After extraction you must see a folder named jdk1.8.0_45. +
6. Update PATH file by opening /etc/profile file by the command

....
sudo nano /etc/profile and paste the following at the end of the file:
JAVA_HOME=/usr/local/java/jdk1.8.0_45
PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
export JAVA_HOME
export PATH
....

> 7. Save and exit. +
8. Tell the system that the new Oracle Java version is available by the
following commands:

....
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jdk1.8.0_45/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/jdk1.8.0_45/bin/javac" 1
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/local/java/jdk1.8.0_45/bin/javaws" 1
....

\9. Make Oracle Java JDK as default by this following commands:

....
sudo update-alternatives --set java /usr/local/java/jdk1.8.0_45/bin/java
sudo update-alternatives --set javac /usr/local/java/jdk1.8.0_45/bin/javac
sudo update-alternatives --set javaws /usr/local/java/jdk1.8.0_45/bin/javaws
....

\10. Reload sytem wide PATH /etc/profile by this command:

....
source /etc/profile
....

\11. Reboot your system.

....
reboot
....

\12. Check Java JDK version by java -version command . If installation
is succesful, it will display like the following:

....
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-xxx)
Java HotSpot(TM) Server VM (build 25.45-xxx, mixed mode)
....

That's it! Note: We Assumed that the downloaded file is named
jdk-8u45-linux-x64.tar.gz and used this name in all the commands used in
steps 2, 4 and 5. It may depends on the type of O.S, processor type
(i.e., 32bit or 64bit)
'''

See a typo, something missing or out of date, or anything else which can be
improved? Edit this document at https://pagure.io/fedora-docs/fedora-howto.
