Cum instalati manual Java 8 pe Ubuntu 16.04

In acest tutorial va prezentam procedura de instalare manuala Java 8 pe Ubuntu 16.04. Instructiunile din acest tutorial functioneaza si pe alte versiuni de Ubuntu incluzand aici versiunile 14.04, 16.10 si 17.04.

Este necesar:

– un editor text vi, vim, emac ..etc

Pasul 1 : Downloadati ultima versiune JDK

Este recomandat sa instalati doar utlima versiune JDK. https://www.oracle.com/technetwork/java/javase/downloads/jdk11-downloads-5066655.html

Pasul 2: Extrageti JDK-ul la locatia implicita Java

Creati directorul jvm in /usr/lib/ care este locatia implicita Java.

# sudo mkdir /usr/lib/jvm

Intrati in directorul nou creat /usr/lib/jvm
# cd /usr/lib/jvm

Extrageti JDK-ul downloadat

# sudo tar -xvzf ~/Downloads/jdk-8u151-linux-x64.tar.gz

Pasul 3: Setati variabilele de environment

Editati fisierul environment

# vi /etc/environment

Actualizati PATH variabilelor adaugand directoarele bin de mai jos separate prin :

/usr/lib/jvm/jdk1.8.0_151/bin:/usr/lib/jvm/jdk1.8.0_151/db/bin:/usr/lib/jvm/jdk1.8.0_151/jre/bin

Directorul HOME poate sa difere in functie de versiune si update, efectuati modificari la acest fisier in functie de versiune :

J2SDKDIR="/usr/lib/jvm/jdk1.8.0_151"
J2REDIR="/usr/lib/jvm/jdk1.8.0_151/jre"
JAVA_HOME="/usr/lib/jvm/jdk1.8.0_151"
DERBY_HOME="/usr/lib/jvm/jdk1.8.0_151/db"

Fisierul environment ar trebui sa fie similar cu acest text:

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/jdk1.8.0_151/bin:/usr/lib/jvm/jdk1.8.0_151/db/bin:/usr/lib/jvm/jdk1.8.0_151/jre/bin"
J2SDKDIR="/usr/lib/jvm/jdk1.8.0_151"
J2REDIR="/usr/lib/jvm/jdk1.8.0_151/jre*
JAVA_HOME="/usr/lib/jvm/jdk1.8.0_151"
DERBY_HOME="/usr/lib/jvm/jdk1.8.0_151/db"

Salvati modificarile si inchideti fisierul.

Pasul 4: Actualizati locatia fisierelor

Utilizati update-alternatives pentru a informa Ubuntu asupra path-urilor de instalare.

# sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.8.0_151/bin/java" 0
# sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.8.0_151/bin/javac" 0
# sudo update-alternatives --set java /usr/lib/jvm/jdk1.8.0_151/bin/java
# sudo update-alternatives --set javac /usr/lib/jvm/jdk1.8.0_151/bin/javac

Pasul 5: Verificarea setup-ului

Specificati locatatia pentru java si javac

# update-alternatives --list java
# update-alternatives --list javac

Restartati sau deschideti un nou terminal.

Pasul 6: Verificati versiunea Java

# java -version

Output-ul trebuie sa fie de forma :

java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)