unit testing - How to debug something that works under Java 7 but not under Java 8 -


i have project unit test works under java 7, not under java 8. there way investigate such things? (i'm sure test correct; suggests there's subtle bug in implementation.)

really suppose quick way identify code paths diverge. hard, because there might sorts of differences in code paths @ low level through jdk, , don't want bogged down in irrelevant differences down tiny optimisations.

so nice thing maybe ask @ top level trace paths diverge; , then, starting before point, ask @ second level trace paths diverge; , on.

but i've no idea whether there's way this. fear waste lot of time if don't have systematic approach.

the code, way, apache phoenix repository, under java 8, following failure:

tests run: 1, failures: 1, errors: 0, skipped: 0, time elapsed: 0.006 sec <<< failure! - in org.apache.phoenix.schema.pmetadataimpltest testeviction(org.apache.phoenix.schema.pmetadataimpltest)  time elapsed: 0.006 sec  <<< failure! java.lang.assertionerror: expected:<3> was:<2>     @ org.junit.assert.fail(assert.java:88)     @ org.junit.assert.failnotequals(assert.java:834)     @ org.junit.assert.assertequals(assert.java:645)     @ org.junit.assert.assertequals(assert.java:631)     @ org.apache.phoenix.schema.pmetadataimpltest.testeviction(pmetadataimpltest.java:98)

one of visible changes between java 7 , java 8 change how hash data structures handle collisions - linked lists used, entries stored in balanced trees. in cases can affect iteration order of these data structures. isn't language regression since these data structures explicitly not specify iteration order, careless code , tests can written assume order.

in rare situations, change introduce change iteration order of hashmap , hashset. particular iteration order not specified hashmap objects - code depends on iteration order should fixed.

~ collections framework enhancements in java se 8

so first thing when debugging java 7 -> 8 failures miss-uses of hashmap, hashset, , concurrenthashmap. once you've found mistake have few choices:

  • replace data structure 1 explicitly provides iteration order, e.g. linkedhashmap, treemap, or immutablemap.
  • remove iteration-order assumptions production code (for instance assuming key/value first element in map).
  • improve tests check specified behavior (which elements) rather unspecified behavior (what order). test data defined in easy-to-write incorrect way, using inline array syntax int[] expected = {1,2,3} , looping on elements. can make easier using guava's static constructors (immutableset.of(1,2,3)) or truth's fluent assertion syntax (assertthat(someset).containsexactly(1, 2, 3)).

if hash ordering proves not root cause issue more subtle , best option step through debugger, suggested. sure @ least skim what's new in jdk 8 clues.


Comments

Post a Comment

Popular posts from this blog

html - Outlook 2010 Anchor (url/address/link) -

i'm trying link specific pdf page msoutlook'10 or msword'10, #page=... anchor particularly useful , works fine elsewhere. unfortunately when click [ctr-k] in outlook or winword, links re-formatted assuming unc path. pdf file located on shared drive. using "file:" prefix links open pdf in adobe reader (outside of browser), , "http:" open inside browser. issue seem need open in browser "file:" prefix in order anchor work. know anchors work inside browser. outlook uses windows/explorer default program (based on file extension) seems open in adobe reader neglecting anchor. is aware of solution, link specific page or bookmark of shared-pdf ms outlook and/or winword link? common references: mailermailer.com/...anchor-tags-html-emails campaignmonitor.com/...anchor-links-in-email-newsletters/ stackoverflow.com/...anchor-in-pdf-document
Read more

javascript - Why does running this loop 9 times take 100x longer than running it 8 times? -

consider code: test = function() { } t = new test(); (var = 0; < 8; i++) { result = t instanceof test; } if change number of iterations 8 9 , loop take 100 times longer complete in latest version of firefox (41.0.1). tested on 2 different pcs , magic limit 8. here jsperf test used: http://jsperf.com/instanceof-8-times-vs-9-times does have idea why might happen? seems specific instanceof . not happen if else object, example check property. note: filed bugzilla bug this. jan de mooij mozilla team has posted details in bugzilla thread . here's simplistic interpretation of highly technical answers: in i < 8 case, firefox smart enough hoist result = t instanceof test; statement out of loop (according tests, doesn't seem omit altogether). in i < 9 case, apparently doesn't optimization . why? reason not clear, related fact 9 iterations threshold above function considered "hot" enough run through jit compiler. i < 8 cas...
Read more

Getting gateway time-out Rails app with Nginx + Puma running on Digital Ocean -

following this guide setup app on digital ocean droplet, not working. site not loading , it's throwing: "gateway time-out". the puma server works, since ps aux | grep puma prints: root 15878 0.0 0.4 376832 2168 ? sl 12:50 0:00 puma 2.13.4 (unix:///var/www/myapp/shared/tmp/sockets/myapp-puma.sock) [20150930164940] root 15881 0.0 0.7 903676 3692 ? sl 12:50 0:06 puma: cluster worker 0: 15878 [20150930164940] root 24654 0.0 0.1 11748 916 pts/2 s+ 18:00 0:00 grep --color=auto puma my nginx config: user root; worker_processes 1; events { worker_connections 1024; } http { upstream puma { server unix:///var/www/myapp/shared/tmp/sockets/myapp-puma.sock; } server { listen 80; server_name myapp.com; root /var/www/myapp/current/public; access_log /var/www/myapp/current/log/access.log; error_log /...
Read more