Dockerfile for a simple Java class

Question

I have the following java class that I would like to write a Dockerfile for so that it can be deployed on a container.

package vowelCounter;

import java.util.Scanner;

public class vowelCounter {
   public static void main(String args[]){
      int count = 0;
      System.out.println("Enter a sentence :");
      Scanner sc = new Scanner(System.in);
      String sentence = sc.nextLine();

      for (int i=0 ; i<sentence.length(); i++){
         char ch = sentence.charAt(i);
         if(ch == 'a'|| ch == 'e'|| ch == 'i' ||ch == 'o' ||ch == 'u'||ch == 'A' ||ch == 'E' ||ch == 'I' ||ch == 'O' ||ch == 'U'){
            count ++;
         }
      }
      System.out.println("Number of vowels in the given sentence is "+count);
   }
}

Would someone please be able to help me with this, I am new to building dockerfiles for various languages, thanks.

Answer 1

Assuming you have the specified class, compiled into a jar, in, let's say, a directory called target/VowelCounter.jar then you can use the following Dockerfile:

    FROM openjdk:11-jre-slim
    COPY target/VowelCounter.jar app.jar
    ENTRYPOINT ["java","-jar","/app.jar"]