I have tried editing the text in the .bat file for the server to "java -Xmx1024M -Xms1024M -jar minecraft_server.jar" and other forms of that and the file will only run with the original text that was there.
java -Xmx512M -Xms1024M -jar minecraft_server.jar -nogui
pause
java -Xmx1024M -Xms512M -jar minecraft_server.jar -nogui
pause