JVM Crash

Ewon Support Basic and Java
#1

Hello, our eWON Java Client recently crashed with the following error in the Realtime log: “ABORT Wonka: tryPutFifo 649: Instance at 0x01933920 has no class!”. An eWON restart had to be done to restart the program.

eWON Firmware version - 14.2

2 questions:

  1. What is Wonka?
  2. Could you tell me what this error means?

A screenshot is attached. Kind regards.

eWON_JvmCrash
eWON_JvmCrash1813×336 42.9 KB

#3

The Wonka VM is an open-source, portable, embedded implementation of the Java virtual machine specification, together with class libraries which implement most of the Connected Device Configuration of Java ME, version 1.0. See: https://en.wikipedia.org/wiki/Wonka_VM

This likely indicates a bug in your program. Is there an object named ‘tryPutFifo’?

Do you get this error continuously, or did this just happen only once?

Can you please create a backup of the Ewon for us using eBuddy and check “Include Support Files”?

#5

Thank you for the quick response.

  1. This error occurred once. No one at my company has seen this error before so we are in the dark.
  2. I’ve searched the eWON client for any instance of ‘tryPutFifo’ - there were none. So this is neither a class, method or variable being called explicitly by the eWON Java code.
  3. I’ve gone through the eWON’s Event logs - the eWON appears to be doing a reboot every 3 days. 3 different reasons are given: a) ‘Unknown’, b) ‘Script request’ (originally in german as ‘Skriptanforderung’) and c) ‘too little memory’ (‘zu wenig Speicher’ - german).
  4. I also notice this error: “Java Critical error: 15” before some of the reboots.
  5. We currently have 369 Tags defined. I read yesterday that the maximum recommended number is 350 (even though 2500 tags for a flexy/cosy) is permissible.
  6. The jvmrun.txt has a heapsize of 5M defined. Is this too little for the number of tags and will increasing it possibly resolve the ‘too little memory’ issue.
  7. Regarding the eWON backup, this is a customer’s eWON and my manager is concerned about exposing any of their data. Is there a way to do an eWON backup whilst obfuscating private information (IP address, pre-shared key, etc)?
#6

All private keys and passwords are hashed in the backup. IP addresses on the internet are public, and private IP addresses are are behind NAT routers, so I’m not sure why that would be a security concern.

The backup will only be accessible to HMS employees for diagnostic purposes and then erased.

#7

Thank you for the information. The backup file (with support files) is attached.dEwonBackup.tar (1.2 MB)

#9

After reviewing the backup, it looks like there are bugs in your code. You are possibly trying to access memory that hasn’t been allocated or trying to access an object that has been deleted. However, without the source code we can’t be sure.

Debugging your code is outside the realm of our support on this forum. I would recommend opening a case at https://mysupport.hms.se where you can get in contact with your local support team.