By default tappAS is using 1.7Gb of RAM if your computer has at least 8Gb, but in some cases it isn't enough to run all analysis. If you have some problems with that you can run tappAS with more RAM if is available.
To do that follow the next steps:
1º Go to tappAS default folder (usually tappas.0.99.xx where xx is your release version)
2º Run the tappas.jar file with the next commant line:
java -XmsAM -XmxBM -jar tappas.jar
Where A and B are the minimum and maximum RAM (in Mb) that you want to give to the app. If you want to give 2Gb as minimun and 6Gb as maximum you need to run:
java -Xms2000M -Xmx6000M -jar tappas.jar
(You need to assign ram in Mb)