B4J Question outofmemoryerror java heap space

[Nokia]

I get this error when trying to encrypt a file over 100 mb or trying to encrypt to many files at the same time. Is there a way to tell the app to get or set a bigger heap space?

or could this be from a memory leak from the encryption?

 

[Nokia]

I can see from task menu every time I encrypt a file it adds memory, but does not release it..

 

[somed3v3loper]

What are you using for encryption ?
You might be missing some Release function ?

 

[Erel]

It is possible to increase the heap size. See the last section in this tutorial: https://www.b4x.com/android/forum/threads/parsing-huge-text-files.34923/#content

However it sounds like there is a memory leak in your solution.

 

[Nokia]

What are you using for encryption ?
You might be missing some Release function ?

jB4XEncryption Library

 

[Nokia]

It is possible to increase the heap size. See the last section in this tutorial: https://www.b4x.com/android/forum/threads/parsing-huge-text-files.34923/#content

However it sounds like there is a memory leak in your solution.

How can I track the memory leak?

I did change the Heap size and was able to encrypt 155 mb file and up to 425 mb worth of a few files..

 

[Erel]

You can use a profiler to check for memory leaks: https://www.b4x.com/android/forum/threads/memory-leak.35729/#post-209766

 

[Nokia]

when I try to use the try and catch to get the message nothing happens. ... no message and the app still closes..

 

[Erel]

You cannot catch out of memory errors.

 

[Nokia]

You cannot catch out of memory errors.

what would you normally do then?

I have put a size restriction on how big a file that can be encrypted but I have noticed.. if you don't have a full dedicated 1024 mb of ram that it will show the out of memory error on a smaller file. on my laptop with 3 gig ram I can run 250mb file but on desktop with 2 gig of ram. I can only do a 100 mb file.

is there a way in code to check available memory?

 

[Erel]

You can use this code to get the reported max heap size:

Sub MaxHeapSize As Long
   Dim jo As JavaObject
   Return jo.InitializeStatic("java.lang.Runtime").RunMethodJO("getRuntime", Null).RunMethod("maxMemory", Null)
End Sub

what would you normally do then?

You should avoid this situation. Recovering from out of memory errors is problematic.

 

[Nokia]

You can use this code to get the reported max heap size:

Sub MaxHeapSize As Long
   Dim jo As JavaObject
   Return jo.InitializeStatic("java.lang.Runtime").RunMethodJO("getRuntime", Null).RunMethod("maxMemory", Null)
End Sub

You should avoid this situation. Recovering from out of memory errors is problematic.

does this code give you the max heap size the app is using or does it give you the max that is available beside what the app is using?

or does it give you how much memory the computer is running?

 

[Erel]

See the exact documentation here: https://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html#maxMemory()

It gives you the maximum heap size that is available for the current process. It is not really related to the physical memory available. You can use the jvm parameters to ask for a higher limit.

 

[derez]

Is it possible to change the max mem size from the b4j application ? I checked the status and it is 256MB and I would like to increase it in a special case that needs more.

 

[Daestrum]

Have a look at this post https://www.b4x.com/android/forum/threads/parsing-huge-text-files.34923/
Erel explains how to use #VirtualMachineArgs towards the end of post #1

 

[derez]

Thank you Daestrum, It solves the problem when running from the IDE but Erel writes there :

Note that #VirtualMachineArgs attribute only affects the program when you run it from the IDE.

I have checked and it is correct so it is not a solution for a user that gets the jar file.
I need a solution that will change the heap as part of the jar file code.

 

[Daestrum]

If you find the setting removes the error, you can supply the same parameters when the user runs the jar.

If you start the jar from a batch file just add the same parameters as the VirtualMachineArgs.

I don't think you can change it from within a jar, as by that stage the JVM has been created.