Yadda ake Shigar Java akan RHEL 8

Java yare ce mai aminci, amintacciya, abin dogaro, kuma sananniya, yaren hada-hadar manufa da kuma dandamali na aikin kwamfuta. Java ba harshe ne kawai ba, dandamali ne na fasaha tare da yawancin damar haɗin gwiwa.

Don gudanar da aikace-aikacen Java akan tsarin RHEL 8 ko sabarku, kuna buƙatar shigar da Java. Kullum kuna buƙatar Java Runtime Environment (JRE), tarin kayan haɗin software da ake amfani dasu don gudanar da aikace-aikacen Java.

A gefe guda kuma, idan kuna son haɓaka aikace-aikace na Java, kuna buƙatar shigar da Kit ɗin Ci gaban Java Oracle (JDK) wanda ya haɗa da cikakkiyar JRE tare da kayan aikin haɓakawa, gyarawa da sa ido kan aikace-aikacen Java. Oracle ne yake goyan bayan Java SE (Standard Edition).

Lura: Idan kuna neman sifofin JDK kyauta, shigar da Oracle OpenJDK wanda ke ba da fasali iri ɗaya da aikin kamar Oracle JDK ƙarƙashin lasisin GPL.

A cikin wannan labarin, za mu nuna muku yadda ake girka OpenJDK 8 da OpenJDK 11, nau'ikan Java biyu masu goyan baya a RHEL 8. Za mu kuma nuna muku yadda za ku girka sabuwar sigar Java OpenJDK 12 don haɓaka da gudanar da aikace-aikacen Java.

RHEL 8 tare da Instananan Shigowa
RHEL 8 tare da Subsaddamar Biyan Kuɗi na RedHat

Yadda ake Shigar OpenJDK a cikin RHEL 8

Don girka OpenJDK akan RHEL 8, da farko sabunta abubuwan kunshin tsarin ta amfani da umarnin dnf kamar yadda aka nuna.

# dnf update

Gaba, girka OpenJDK 8 da 11 ta amfani da dokokin da ke tafe.

# dnf install java-1.8.0-openjdk-devel  	#install JDK 8
# dnf install java-11-openjdk-devel		#install JDK 11

Da zarar tsarin shigarwa ya cika, zaku iya bincika sigar Java da aka girka ta amfani da umarni mai zuwa.

# java -version

Sakamakon aikin umarnin da ke sama ya nuna cewa Java 8 shine fasalin tsoho.

Yadda ake Shigar OpenJDK 12 akan RHEL 8

Abun takaici, RHEL 8 baya bayarwa ko tallafawa Java 12 ta tsoho. Amma zaka iya zazzage shirye-shiryen shirye-shirye OpenJDK 12 daga nan kuma shigar da shi kamar yadda aka nuna.

# cd opt
# wget -c https://download.java.net/java/GA/jdk12.0.2/e482c34c86bd4bf8b56c0b35558996b9/10/GPL/openjdk-12.0.2_linux-x64_bin.tar.gz
# tar -xvf openjdk-12.0.2_linux-x64_bin.tar.gz

Don bincika sigar Java, dole ne kuyi amfani da cikakkiyar hanya zuwa binary kamar yadda aka nuna.

# ./opt/jdk-12.0.2/bin/java -version

Mahimmi: Don amfani da Java 12 azaman sigar tsoho, dole ne a tantance shi azaman ƙimar canjin yanayin JAVA_HOME kamar yadda aka bayyana a sashe na gaba.

Yadda zaka saita JAVA_HOME Mai Muhalli Mai Sauyi a RHEL 8

Idan kuna da nau'ikan Java da yawa da aka sanya akan tsarin ku, zaku iya zaɓar sigar da kuke son amfani da ita ta hanyar tsohuwa, ta hanyar amfani da layin umarni da ake kira madadin ko saita yanayin yanayin JAVA_HOME don zaɓar JDK bisa tsarin aikace-aikacen-aikace.

Bari mu duba batutuwa masu wahala kamar yadda aka bayyana a ƙasa.

Amfani da madadin, kuna buƙatar sauya fasalin java (wanda ke ƙaddamar da aikace-aikacen Java) da javac (wanda ke karanta ajin aji da maɓallin kewayawa kuma ya tsara su cikin fayilolin aji) binaries a duniya kamar yadda aka nuna.

Farawa tare da java, zaɓi nau'in da kuke so ta amfani da lambar zaɓi kuma latsa shiga kamar yadda aka nuna a cikin hoton hoton. Sannan tabbatar cewa tsoffin sigar an sauya zuwa abin da kuke so.

# alternatives --config java
# java -version

Hakanan, canza javac zuwa sigar Java da kake son amfani da ita kamar yadda aka nuna.

# alternatives --config javac
# javac -version

Canjin yanayi na JAVA_HOME yana tantance kundin adireshi inda aka sanya JRE akan tsarinku. Lokacin da aka saita, aikace-aikacen Java daban-daban da sauran shirye-shirye suna amfani dashi don nemo inda aka sanya Java: Siffar Java ɗin da aka ƙayyade shine wanda ake amfani dashi don aiwatar da aikace-aikace.

Zaku iya saita shi a cikin/sauransu/muhalli tsarin farawa harsashi na duniya kamar yadda aka nuna.

# vim /etc/environment

Sa'an nan kuma ƙara layi mai zuwa a cikin fayil ɗin (maye gurbin /opt/jdk-12.0.2/ tare da cikakkiyar hanyar zuwa kundin shigarwa na JVM 8 ko JVM 11 kamar yadda aka nuna a cikin fitowar kayan amfanin da ke sama).

export JAVA_HOME=/opt/jdk-12.0.2/

Adana fayil ɗin kuma rufe shi. Sannan samo shi kamar haka.

# source /etc/environment

Kuma yanzu idan ka bincika ƙimar canjin yanayin JAVA_HOME, yakamata ya nuna kundin shigarwa na JRE da kake son amfani dashi.

# echo $JAVA_HOME

Kun zo karshen wannan darasin. A cikin wannan jagorar, kun koyi yadda ake girka Java a cikin RHEL 8 kuma saita canjin JAVA_HOME. Idan kuna da tambayoyi, ƙari ko tsokaci, da fatan za a gabatar da su ta hanyar fom ɗin da ke ƙasa.