Failed to import a definition

Hello everyone,

Recently while I'm trying to import an API definition in ReadyAPI, I'm getting "Failed to import a definition" error. But I can see the imported json under specification. 

After I tried to update definition and I'm getting heap space error, but I set up max heap size as 8GB in vmoptions file.

Please suggest possible way to import this successfully. Thanks!

Note: File which I'm trying to import is having ~120 endpoints. But this is an issue?