memory leak java <-> javascript when java returns []array

[patricklx]

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 5.3.1
• Cross-platform modules: 5.3.1
• Android Runtime: 5.3.1
• iOS Runtime (if applicable):
• Plugin(s):

Describe the bug

We observe a memory leak when we have the following call thread:
this was to reproduce the ble pattern, but I tested again and I see the leak with only getValue. Looks like it only happens when byte[] is returned. Same issue when String[] is returned.
https://github.com/patricklx/ns-memory-leak/blob/master/app/App_Resources/Android/src/main/java/my/Test.java#L25

I did few memory snapshots, and what is beeing left over is a lot of
system / FunctionTemplateInfo and system / ObjectTemplateInfo

NOTE:
we do not have a memory leak if the getValue does not return the value

markingMode: none, does not help either.

Expected behavior
GC should collect the java array

Sample project
https://github.com/patricklx/ns-memory-leak

this can also be observed with the ble plugin,
since its the same pattern:
https://github.com/EddyVerbruggen/nativescript-bluetooth/blob/master/src/android/TNS_BluetoothGattCallback.ts#L212

[patricklx]

@vtrifonov can you also have a looks at this one? its a huge issue for us. We have bluetooth connected to a few devices that send many events

[vtrifonov]

@patricklx what tool did you use to take and compare the memory snapshots?

[patricklx]

@vtrifonov I used the chrome devtools memory snapshots

[vtrifonov]

We found a problem when creating Array Wrappers which seems to leak memory because of the ObjectTemplates being created every time. However arrays need more memory than a string as we attach some callbacks to them so that they can work in the JS.

[patricklx]

thanks. we tried out the latest snapshot, and memory usage is quite stable!
We had some issues with the tns build android with that new runtime though, we have to run tns build twice, seems some files are not integrated into the apk as resources correctly at first time build. e.g_: app/App_Resources/Android/src/main/res/values/nativescript_google_maps_api.xml

[vhristov5555]

Could you please try to delete platforms folder and try to build it again. If you could reproduce the problem could please open a new issue with some steps to reproduce it(e.g. files missing) so we could be able to fix it.