Computer Science
Greenfoot Games:
spritegame package
My preferred Online Integrated Development Tool for Java and Python
When using repl sign, if you have a Google account, be sure to sign in with it. You will have to make a username, but you can easily login with Google each time. To code in Java, make a class called Main, then make as many other classes as you like - just don't make them public. You can also enter project mode to use multiple files.
Some other Online Java and/or Python IDEs