Java garbage collection due to Metadata GC Threshold when metaspace occupancy is less than its maximum capacity

Issue

• A Metadata GC Threshold triggering a collection despite the GC logging showing plenty of available Metaspace. For example, in the following GC log entry the Metaspace occupancy is 256590K, and the Metaspace capacity is 1230848K:

  [Full GC (Metadata GC Threshold) 308976.826: [CMS: 50324K->50420K(1756416K), 0.2793245 secs] 296498K->50420K(2063104K), [Metaspace: 256590K->256590K(1230848K)], 0.2799017 secs]