ConcurrentAccessException on CodeObject.children

Hmm. Perhaps this is the cause, and if it is I believe the call site can be synchronized to avoid making CodeObject/CodeObjectTree thread safe:
https://github.com/applandinc/appmap-java/blob/less-mem_20200817/src/main/java/com/appland/appmap/record/Recorder.java#L110-L113

In short, writeEvent used to be synchronized. It's no longer synchronized due to the fact that we can encounter a lock when calling toString into the client application. It's certainly worth looking into. I'll defer to you @apotterri if you'd like to look into it now or as a follow on item.

Originally posted by @dustinbyrne in https://github.com/applandinc/appmap-java/pull/29#discussion_r475896188

110-113行目で参照されているwriteEventの呼び出し箇所にあるRecorder.javaから始め、報告された並行アクセスの経路についてCodeObject.childrenとCodeObjectTreeを調査してください。同期されていないwriteEventがConcurrentAccessExceptionを引き起こすかを再現するか、別の方法で確認し、その失敗に対する検証済みの解決策を確立してください。