ubuntu中运行java程序

rivsidn@rivsidn:~/demo/java$ sudo apt-cache search jdk
default-jdk - Standard Java or Java compatible Development Kit

rivsidn@rivsidn:~/demo/java$ sudo apt-get install default-jdk

rivsidn@rivsidn:~/demo/java$ cat Welcome.java 
public class Welcome
{
    public static void main(String[] args)
    {
        String greeting = "Welcome to Core Java!";
        System.out.println(greeting);
    }
}

rivsidn@rivsidn:~/demo/java$ javac Welcome.java 
rivsidn@rivsidn:~/demo/java$ java Welcome 
Welcome to Core Java!