You should create an account on repl.it. Then the website will save your files.
To create a 'repl':
- Click on 'Start coding'
- Click on 'Java'
- Click on 'Create repl'
- In the left column, click on the small icon that says 'Add file' when you hover over it.
- In the blank box, enter the name of the Java file that you want to run. For example: convertTemps.java.
- Copy-paste the contents of the Java file into the middle window.
An issue with repl.it is that the class Main.java is always present. If you click Run, Main.java runs but your program doesn't. To get your program to run, edit Main.java. For example, if your program is 'convertTemps.java', edit Main.java so that it looks like this:
public static void main(String args)
This will get Main.java to run your program.
To run a different program, substitute the program name for 'convertTemps' in Main.java.