mkdir /usr/local/java

tar -zxvf jdk-8u231-linux-x64.tar.gz -C /usr/local/java/

vim /etc/profile

#Java Env
export JAVA_HOME=/usr/local/java/jdk1.8.0_231
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin

source /etc/profile

vim Hello.java 

public class Hello
{
   public static void main(String[] args)
   {
      System.out.println("hello, world");
   }

}

javac Hello.java