I guess Weka is the official tool of each Msc in CS student.
I was trying to work with Weka on a relatively large data, ~50k rows, it gave me this java heap error. The trick is running weka with an additional flag.
By default its memory is less than 128mb I guess, I was generous and gave 1024mb, you can tweak it according to your computer’s memory plus your task’s consumption
java -jar weka.jar -Xmx1024m