fix: check for null when MBeanInfo is incomplete (#1529)

Signed-off-by: Valéry Fouques <48053275+BZValoche@users.noreply.github.com>
Signed-off-by: BZValoche <valery.fouques@free.fr>

Author: BZValoche

collector/src/main/java/io/prometheus/jmx/JmxScraper.java

@@ -415,6 +415,12 @@ private void scrapeBean(MBeanServerConnection beanConn, ObjectName mBeanName) {
                 }
 
                 MBeanAttributeInfo mBeanAttributeInfo = name2MBeanAttributeInfo.get(attributeName);
+                if (mBeanAttributeInfo == null) {
+                    LOGGER.trace(
+                            "%s returned attribute '%s' that is not present in its MBeanInfo. Skipping.",
+                            mBeanName, attributeName);
+                    continue;
+                }
                 LOGGER.trace("%s_%s process", mBeanName, mBeanAttributeInfo.getName());
                 processBeanValue(
                         mBeanName,