Null Pointer response in discover()
Closed this issue · 8 comments
This line occurs twice in the discover() method:
CoapResponse response = client.get();
The first one (for the devices) always gives me Null Pointers on my Raspberry Pi 2.
It always works on my Laptop, where I have my IDE for debugging...
Communication with the gateway from the Pi also works (tested with coap-client from libcoap).
Documentation says that get() "... blocks until the response is available".
I don't get why this error only occurs only on my Pi 2, will also test on my Pi 3 now...
OK, on my Pi 3, this problem does not occur, very strange.
On a side note I like to point out that installation of maven in Raspbian causes a JDK7 to get installed and prioritized higher than your out-of-the-box JDK8, then you will get errors because the TRADFRI2MQTT pom.xml wants a Java 1.8 target.
Fix it with:
sudo update-alternatives --config java
found here: http://www.savagehomeautomation.com/projects/raspberry-pi-change-default-java-virtual-machine-jvm.html
I'm seeing this as well on a pi, both Oracle and OpenJDK 8. I'll tweak the build to generate 7.0 compatible bytecode so it can run on both
It's running fine on OpenJDK 7 on my Pi 2. I'll check in the pom.xml changes (plus the test for colour temp as my bulb [TRADFRI bulb E27 opal 1000lm] isn't reporting that value)
This commit didn't change the line that gives me Null Pointers. I only have full white spectrum bulbs, I guess your commit was to fix issues with the bulbs that only have one temperature.
Currently, it is in line 182 in Main.java, this is where I get a NullPointerException, because CoapResponse response = client.get(); is null.
Changing the Java version didn't change this issue.
Did you rebuild with the Java 7.0 bytecode and run it with OpenJDK 7?
My best guess is that this is a JIT issue on ARM so you could try running with the -Xint command line arg.
It will be REALLY slow but it will confirm if it's the JIT
Actually it's running for me with Oracle Java 7.0 it's working with, but I've just tried the 8.0 and -Xint and it's still throwing a NPE
OK, fixed it with Java 8 as well. The doc is not great, but client.get() can return null when a response times out. The timeout defaults to 2 seconds, you can increase it by editing the Californium.properties file.
Edit the ACK_TIMEOUT value. 4000 seams to work for me
ACK_TIMEOUT=4000
That helps indeed, thanks a lot