Install JDK 92017/09/25

	Install Java SE Development Kit 9 (JDK9) and build Java Environment.
[1]	Download and install JDK 9. Make sure the latest version and source URL of JDK on Oracle download site.

[root@dlp ~]#

curl -LO -H "Cookie: oraclelicense=accept-securebackup-cookie" \
"http://download.oracle.com/otn-pub/java/jdk/9+181/jdk-9_linux-x64_bin.rpm"

[root@dlp ~]#

rpm -Uvh jdk-9_linux-x64_bin.rpm

Preparing...                          ################################# [100%]
Updating / installing...
   1:jdk-9-2000:9-ga                  ################################# [100%]
Unpacking JAR files...
        plugin.jar...
        javaws.jar...
        deploy.jar...

[root@dlp ~]#

java -version

java version "9"
Java(TM) SE Runtime Environment (build 9+181)
Java HotSpot(TM) 64-Bit Server VM (build 9+181, mixed mode)

[root@dlp ~]#

vi /etc/profile

# add follows to the end

export JAVA_HOME=/usr/java/default
export PATH=$PATH:$JAVA_HOME/bin
export CLASSPATH=.:$JAVA_HOME/jre/lib:$JAVA_HOME/lib:$JAVA_HOME/lib/tools.jar

[root@dlp ~]#

source /etc/profile

[2]	If another version of JDK had been installed, change the default like follows.

[root@dlp ~]#

alternatives --config java


There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64/jre/bin/java
   2           /usr/java/jdk-9/bin/java

# select the latest one
Enter to keep the current selection[+], or type selection number: 2

[3]	Create a test program and make sure if it works normally.

[root@dlp ~]#

vi day.java

import java.util.Calendar;

class day {
    public static void main(String[] args) {
        Calendar cal = Calendar.getInstance();
        int year = cal.get(Calendar.YEAR);
        int month = cal.get(Calendar.MONTH) + 1;
        int day = cal.get(Calendar.DATE);
        int hour = cal.get(Calendar.HOUR_OF_DAY);
        int minute = cal.get(Calendar.MINUTE);
        System.out.println(year + "/" + month + "/" + day + " " + hour + ":" + minute);
    }
}

# compile

[root@dlp ~]#

javac day.java

# run

[root@dlp ~]#

java day

2017/9/26 19:47

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