Github user upthewaterspout commented on a diff in the pull request: https://github.com/apache/incubator-geode/pull/299#discussion_r90077848 --- Diff: geode-core/src/main/java/org/apache/geode/internal/statistics/StatMonitorHandler.java --- @@ -50,36 +50,26 @@ public StatMonitorHandler() { /** Adds a monitor which will be notified of samples */ public boolean addMonitor(StatisticsMonitor monitor) { - synchronized (this) { - boolean added = false; - List<StatisticsMonitor> oldMonitors = this.monitors; - if (!oldMonitors.contains(monitor)) { - List<StatisticsMonitor> newMonitors = new ArrayList<StatisticsMonitor>(oldMonitors); - added = newMonitors.add(monitor); - this.monitors = Collections.unmodifiableList(newMonitors); - } - if (!this.monitors.isEmpty()) { - startNotifier_IfEnabledAndNotRunning(); - } - return added; + boolean added = false; + if (!this.monitors.contains(monitor)) { + added = this.monitors.add(monitor); + } + if (!this.monitors.isEmpty()) { + startNotifier_IfEnabledAndNotRunning(); } + return added; } /** Removes a monitor that will no longer be used */ public boolean removeMonitor(StatisticsMonitor monitor) { - synchronized (this) { - boolean removed = false; - List<StatisticsMonitor> oldMonitors = this.monitors; - if (oldMonitors.contains(monitor)) { - List<StatisticsMonitor> newMonitors = new ArrayList<StatisticsMonitor>(oldMonitors); - removed = newMonitors.remove(monitor); - this.monitors = Collections.unmodifiableList(newMonitors); - } - if (this.monitors.isEmpty()) { - stopNotifier_IfEnabledAndRunning(); - } - return removed; + boolean removed = false; --- End diff -- Same issue here - it's not safe to remove the synchronization.
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