InfinispanCacheMeterBinder throws NullPointerException when statistics-available="false"

[asmirnou]

Describe the bug

When cache is simple, statistics is not available and Infinispan embedded metrics are exposed using Micrometer, the following exception occurs:

Caused by: java.lang.NullPointerException: null
	at org.infinispan.spring.starter.embedded.actuator.InfinispanCacheMeterBinder.size(InfinispanCacheMeterBinder.java:31) ~[infinispan-spring-boot-starter-embedded-2.3.4.Final.jar:2.3.4.Final]
	at io.micrometer.core.instrument.binder.cache.CacheMeterBinder.bindTo(CacheMeterBinder.java:49) ~[micrometer-core-1.5.6.jar:1.5.6]
	at org.springframework.boot.actuate.metrics.cache.CacheMetricsRegistrar.bindCacheToRegistry(CacheMetricsRegistrar.java:65) ~[spring-boot-actuator-2.3.5.RELEASE.jar:2.3.5.RELEASE]

To Reproduce

Steps to reproduce the behavior:

1. Clone this repo https://github.com/asmirnou/infinispan-spring-boot-npe
2. Run ./gradlew bootRun
3. The exception above is thrown

Expected behavior

InfinispanCacheMeterBinder handles the case when getStats() returns null if cache is of type SimpleCacheImpl.

Additional context

The situation simulated in the demo project occurs in a real Spring Boot application when Hibernate 2nd level cache default configurations are used and Micrometer metrics are present.

<local-cache-configuration name="pending-puts" simple-cache="true" statistics="false" statistics-available="false">

[karesti]

thank you @asmirnou ! I will open a jira