ServiceLoader didn't find any services registered under com.hazelcast.instance.NodeExtension

[anil kumar]

Hi,

Getting the below exception, while trying to create HazelcastInstance. 

Hazelcast version being used is 3.12.10.

Didn't get this issue while we were using 4.1

Any inputs in resolving this issue?

Caused by: com.hazelcast.core.HazelcastException: ServiceLoader didn't find any services registered under com.hazelcast.instance.NodeExtension

at com.hazelcast.instance.NodeExtensionFactory.create(NodeExtensionFactory.java:86) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.DefaultNodeContext.createNodeExtension(DefaultNodeContext.java:59) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.Node.<init>(Node.java:225) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.HazelcastInstanceImpl.createNode(HazelcastInstanceImpl.java:161) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.HazelcastInstanceImpl.<init>(HazelcastInstanceImpl.java:131) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.HazelcastInstanceFactory.constructHazelcastInstance(HazelcastInstanceFactory.java:203) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.HazelcastInstanceFactory.newHazelcastInstance(HazelcastInstanceFactory.java:182) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.instance.HazelcastInstanceFactory.newHazelcastInstance(HazelcastInstanceFactory.java:132) ~[hazelcast-enterprise-all-3.12.10.jar:?]

at com.hazelcast.core.Hazelcast.newHazelcastInstance(Hazelcast.java:57) ~[hazelcast-enterprise-all-3.12.10.jar:?]

Thanks,

Anil

[anil kumar]

We have tried to debug this further, and please find our analysis below

• we have hazelcast-enterprise-all jar imported into the database and all classes are loaded from database.  
  
• Noticed that In hazelcast 'ServiceLoader' class, for loading the class 'com.hazelcast.instance.NodeExtension',  URLDefinition is being created from the custom classloader(given in our configuration while creating hazelcastInstance)
• The url being created is of the form 'myjdbc://839304950:0/hazelcast-enterprise-all-3.12.10.jar!/META-INF/services/com.hazelcast.instance.NodeExtension'
• In 3.12.10 version, ServiceLoader class is getting URL from classloader and converting it to URI(in collectFactoryUrls method) and storing it in ServiceLoader.URLDefinition as URI.
• parse() method is trying to convert URI to URL(urlDefinition.uri.toURL()), but is failing with MalformedURLException(unknown protocol: myjdbc) while parsing the factory url 'myjdbc://839304950:0/hazelcast-enterprise-all-3.12.10.jar!/META-INF/services/com.hazelcast.instance.NodeExtension'
• But the same is working fine in 4.1 as ServiceLoader.URLDefinition class has both URL and URI fields and hence conversion is not needed. It is loading the class successfully.  
  

Is this an issue in 3.12.10 ?

Can you let us know if there is a possible workaround to get past this issue?

Thanks,

Anil

[Jaromir Hamala]

Hello Anil,

can share some details about your environment? Ideally a reproducer. If you cannot share this then just a simple description of your environment (application server? how is Hazelcast deployed?) will help.

Cheers,

Jaromir

[anil kumar]

Hi Jaromir,

Thanks for the prompt response.

Application Server : tomcat

Hazelcast deployment mode : Embedded

For our framework to work, we load all the external and internal classes(jars) to the database and our classloader fetches them from the database.

Let us know if any other info is required.

[Jaromir Hamala]

Do you have a custom classloader to load classes stored in a database? Or do you use an open source library for this?

Cheers,

Jaromir

[anil kumar]

It is a custom classloader.

Thanks,

Anil

[Jaromir Hamala]

and I am assuming hazelcast.jar is stored in the DB too, is that right?

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[anil kumar]

Yes

[Jaromir Hamala]

Please create an issue at https://github.com/hazelcast/hazelcast/issues/new/choose

and document your environment. I believe we should be able to backport the change from 4.x.

Cheers,

Jaromir

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[anil kumar]

I will create an issue.

Any ETA for the fix to be available in 3.12.x version?

Or is there any workaround that we can leverage to get past the issue for now?

Thanks,

Anil

[Jaromir Hamala]

No ETA unfortunately. It has to be analyzed from a risk perspective - any regression in a patch release is costly.

The only workaround I can think of is to load Hazelcast by using a regular classloader. Or perhaps you could try to register a dummy URL handler for "myjdbc". That could possibly prevent the MalformedURLException(unknown protocol: myjdbc) exception.

Cheers,

Jaromir

[anil kumar]

hi Jaromir,

Can you provide more details regarding the workaround 'register a dummy URL handle for myjdbc' ?

Thanks,

Anil