Memory leaking in unload world

[fixca]

Describe the issue
I copied my world with clone() method.
And I did

Bukkit.unloadWorld(world, false);
Bukkit.getWorlds().remove(world);

But seems world isnt unload correctly...
This is my heap dump. Hope It will be helpful.

https://drive.google.com/file/d/1PPdzB6yGmW3pZ1ra-pGYx8ly0YvzMKtG/view?usp=sharing

Spigot version
1.8.8

Plugin version
latest

[t3rry327]

world = null after that 2 lines should free the memory. (gc will handle it auto, but if u want to do it manually, just call System.gc() from the main thread)

[felipepasc]

I'm having the same problem, and I detected that worldedit was keeping the maps in RAM, preventing Java's gc from cleaning it