As cuixiaoyiyi puts it on github: "An anonymous inner class will hold a reference to the this pointer of the outer class and will not be released until the thread ends. It will hold the Activity and prevent its timely release."

Imagine you have a domain-object which is organized in a tree structure. Additionally there are detached objects that reference a part of this structure. Now you need to collect some value from the referenced portion of the tree. You can identify the TreeOrganizedObjects by their UUID. Here is how you can do it in Java:

When dealing with entities that have many references, you might encounter the BooleanQuery.maxClauseCount which is 1024 by default. This value is already pretty high. But if a query exceeds this value, you should be aware that this is a warning indicator for your performance. 

A TermsQuery might be more appropriate in this case, looking somewhat like

result = result.filter(f.terms().field("entity_id").matchingAny(idList.stream().map(idToSearch -> String.valueOf(idToSearch)).collect(Collectors.toList())));