How to solve Minecraft eula.txt error?

The Java server does not complete the boot without accepting the EULA terms. Check that the file is organized in the correct server folder.

Step by step

Initialize the server jar once. It is normal for the boot to stop, wait for eula.txt to occur in the same working directory.
Read the Minecraft EULA terms from the link in the file. If you agree, change the line eula=false to eula=true and save it as plain text.
If the startup file is running from a different directory, verify that you are editing the correct file. Make sure you don't accidentally create eula.txt.txt by turning on extensions in Windows.
Restart jar file. If the EULA message is passed and world preparation begins, this step has been resolved.

If the file does not create at all, first check for Java, working directory and file write permission issues.