public Integer getMaximum() {
    return maximum;
  }
The unit of this value is determined by the definition of the {@link EvictionAlgorithm} set by
one of the creation methods e.g. {@link EvictionAttributes#createLRUEntryAttributes()}

For algorithm LRU HEAP null will be returned

@return maximum value used by the {@link EvictionAlgorithm} which determines when the
        {@link EvictionAction} is performed.
geode-core/src/main/java/org/apache/geode/management/EvictionAttributesData.java