Should I download the compiler?

Answer 1

JDK offered by Oracle contains compiler

Answer 2

I have downloaded JDK ,so what I do?

Answer 3

Write your java code with main function on text file with .java extension (test.java), then go to the console and run this command

javac test.java

Run this command to see the executable output

java test

To compile multiple files (project) is best to use an IDE like NetBeans or Eclipse