ThreadLocal leaks of org.apache.lucene.document.DateTools objects

[vladak]

It seems that after the recent update of Lucene to 8 (#2880) some ThreadLocal leaks were introduced. From catalina.out:

13-Aug-2019 13:32:24.008 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [source] created a ThreadLocal with key of type [org.apache.lucene.document.DateTools$1] (value [org.apache.lucene.document.DateTools$1@207700b2]) and a value of type [java.util.GregorianCalendar] (value [java.util.GregorianCalendar[time=1553529124000,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="GMT",offset=0,dstSavings=0,useDaylight=false,transitions=0,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2019,MONTH=2,WEEK_OF_YEAR=13,WEEK_OF_MONTH=5,DAY_OF_MONTH=25,DAY_OF_YEAR=84,DAY_OF_WEEK=2,DAY_OF_WEEK_IN_MONTH=4,AM_PM=1,HOUR=3,HOUR_OF_DAY=15,MINUTE=52,SECOND=4,MILLISECOND=0,ZONE_OFFSET=0,DST_OFFSET=0]]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
13-Aug-2019 13:32:24.008 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [source] created a ThreadLocal with key of type [org.apache.lucene.document.DateTools$2] (value [org.apache.lucene.document.DateTools$2@349b77e1]) and a value of type [java.text.SimpleDateFormat[]] (value [[Ljava.text.SimpleDateFormat;@78ea6ba7]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.