OpenJDK 11 : Install

 Install OpenJDK 11.

[1]. If you need only JRE, Install only [java-11-openjdk] package,

but if you need compiler, Install [java-11-openjdk-devel] package, too.

[root@dlp ~]# dnf -y install java-11-openjdk java-11-openjdk-devel

[root@dlp ~]# cat > /etc/profile.d/java.sh <<'EOF'

export JAVA_HOME=$(dirname $(dirname $(readlink $(readlink $(which java)))))

export PATH=$PATH:$JAVA_HOME/bin

EOF

[root@dlp ~]# source /etc/profile.d/java.sh

[root@dlp ~]# java --version

openjdk 11.0.5 2019-10-15 LTS

OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS)

OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing)

# verify to create test program

[root@dlp ~]# cat > java_test.java <<'EOF'

class java_test {

    public static void main(String[] args) {

        System.out.println("Hello Java World !");

    }

}

EOF 

[root@dlp ~]# javac java_test.java

[root@dlp ~]# java java_test

Hello Java World !

[2]. If you installed multiple version of Java from CentOS official repository, it's possbile to switch them with [alternatives].

[root@dlp ~]# alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command

-----------------------------------------------

   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.5.10-0.el8_0.x86_64/bin/java)

*+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el8_0.x86_64/jre/bin/java)


Enter to keep the current selection[+], or type selection number: 1


[root@dlp ~]# alternatives --config javac

There are 2 programs which provide 'javac'.

  Selection    Command

-----------------------------------------------

   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.5.10-0.el8_0.x86_64/bin/javac)

*+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el8_0.x86_64/bin/javac)

Enter to keep the current selection[+], or type selection number: 1

[root@dlp ~]# java --version

openjdk 11.0.5 2019-10-15 LTS

OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS)

OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing)

[root@dlp ~]# javac --version

javac 11.0.5

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