java - setContextClassLoader implications -


i'm trying clean tomcat warnings memory leaks due creating own threads. http://wiki.apache.org/tomcat/memoryleakprotection proposes call mythread.setcontextclassloader(null) prior starting thread.

what implication of call? code in run() method still able resolve classes application?

yes will. thread.getcontextclassloader() mechanism generic frameworks load resources further down class loader tree.

take tomcat's class loader hierarchy.

      bootstrap           |        system           |        common        /     \   webapp1   webapp2 ...

the servlet or jsp framework resides in common class loader. if 1 of these frameworks load classpath resource webapp1, try:

getclass().getresource("/some/resource/in/webapp1"); // fail

but since class loading mechanics delegates calls class loader chain, fail. means frameworks needs load resource instead do:

thread.currentthread().getcontextclassloader().getresource("/some/resource/in/webapp1");

and servlet container makes sure webapp1 class loader whenever thread executing in context. thread's context classloader way frameworks load classes "the wrong direction".

when spawn new thread, thread gets, default context class loader of parent (your webapp1 classloader). if consequently stop webapp1, tomcat supposed able gc webapp, unable long there's reference left webapp1 class loader - hence warning.

good article context class loaders.


Comments

Post a Comment

Popular posts from this blog

asp.net - repeatedly call AddImageUrl(url) to assemble pdf document -

i'm using abcpdf , i'm curious if can recursively call addimageurl() function assemble pdf document compile multiple urls? something like: int pagecount = 0; int theid = thedoc.addimageurl("http://stackoverflow.com/search?q=abcpdf+footer+page+x+out+of+", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetochain(theid); } pagecount = thedoc.pagecount; console.writeline("1 document page count:" + pagecount); //flatten document (int = 1; <= pagecount; i++) { thedoc.pagenumber = i; thedoc.flatten(); } //now try again theid = thedoc.addimageurl("http://stackoverflow.com/questions/1980890/pdf-report-generation", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetoc...
Read more

java - Android recognize cell phone with keyboard or not? -

in android app, want detect user's device if device has keyboard(like motorola milestone) , show corresponding user interface. guys know how that? ! regards justicepenny http://developer.android.com/reference/android/content/res/configuration.html public int keyboard the kind of keyboard attached device. 1 of: keyboard_nokeys, keyboard_qwerty, keyboard_12key. that's it!
Read more

iphone - How would you achieve a LED Scrolling effect? -

how achieve led scrolling effect example below? led sign - led ticker emulator iphone , ipad http://img.skitch.com/20101201-rsfh4p1bajb1wp94k466pdpiuj.preview.jpg sometimes remunerates comment in other posts :) have put code you, should implement font '8pin matrix' realistic feeling. uilabel *label; - (void)viewdidload { [super viewdidload]; label = [[uilabel alloc]initwithframe:cgrectmake(10, 50, 300, 20)]; label.font = [uifont fontwithname:@"courier-bold" size:16.0]; label.backgroundcolor = [uicolor blackcolor]; label.textcolor = [uicolor greencolor]; label.linebreakmode = uilinebreakmodecharacterwrap; // otherwise "…" label.text = @"this led text scrolled "; // blanks space between [self.view addsubview:label]; [nstimer scheduledtimerwithtimeinterval:0.12f target:self selector:@selector(scrolllabel) use...
Read more