FindBugs™ - Find Bugs in Java Programs

This is the web page for FindBugs, a program which uses static analysis to look for bugs in Java code. It is free software, distributed under the terms of the Lesser GNU Public License. The name FindBugs™ and the FindBugs logo are trademarked by The University of Maryland. As of July, 2008, FindBugs has been downloaded more than 700,000 times.

FindBugs requires JRE (or JDK) 1.5.0 or later to run. However, it can analyze programs compiled for any version of Java. The current version of FindBugs is 1.3.9, released on 16:39:49 EDT, 21 August, 2009. We are very interested in getting feedback on how to improve FindBugs.

Changes | Talks | Papers | Sponsors | Support

New

JavaOne talk: Slides from my JavaOne talk, Mistakes That Matter.
FindBugs community review: We are previewing FindBugs community review, in which anyone can review issues in open source projects (i.e., mark issues as "must fix" or "mostly harmless"), and those reviews are automatically shared with other reviewers.
This is a pre-beta release, not ready for deployment. The implementation will be undergoing significant changes before general availability.
Initially, we are posting results for:
- Sun's JDK 7
- Eclipse 3.5
Google FindBugs Fixit: Google has a tradition of engineering fixits, special days where they try to get all of their engineers focused on some specific problem or technique for improving the systems at Google. A fixit might work to improve web accessibility, internal testing, removing TODO's from internal software, etc.
On May 13-14, Google held a global fixit for UMD's FindBugs tool a static analysis tool for finding coding mistakes in Java software. The focus of the fixit was to get feedback on the 4,000 highest confidence issues found by FindBugs at Google, and let Google engineers decide which issues, if any, needed fixing.
More than 700 engineers ran FindBugs from dozens of offices. More than 250 of them entered more than 8,000 reviews of the issues. A review is a classification of an issue as must-fix, should-fix, mostly-harmless, not-a-bug, and several other categories. More than 75% of the reviews classified issues as must fix, should fix or I will fix. Many of the scariest issues received more than 10 reviews each.
Engineers have already submitted changes that made more than 1,100 of the 3,800 issues go away. Engineers filed more than 1,700 bug reports, of which 600 have already been marked as fixed Work continues on addressing the issues raised by the fixit, and on supporting the integration of FindBugs into the software development process at Google.
The fixit at Google showcased new capabilities of FindBugs that provide a cloud computing / social networking backdrop. Reviews of issues are immediately persisted into a central store, where they can be seen by other developers, and FindBugs is integrated into the internal Google tools for filing and viewing bug reports and for viewing the version control history of source files. For the Fixit, FindBugs was configured in a mode where engineers could not see reviews from other engineers until they had entered their own; after the fixit, the configuration will be changed to a more open configuration where engineers can see reviews from others without having to provide their own review first. These capabilities have all been contributed to UMD's open source FindBugs tool, although a fair bit of engineering remains to prepare the capabilities for general release and make sure they can integrate into systems outside of Google. The new capabilities are expected to be ready for general release in Fall 2009.

Change history

The current version of FindBugs is s 1.3.9.

Changes since version 1.3.7

Primarily another small bugfix release.
FindBugs base:

New Reports:

SF_SWITCH_NO_DEFAULT: missing default case in switch statement.
SF_DEAD_STORE_DUE_TO_SWITCH_FALLTHROUGH_TO_THROW: value ignored when switch fallthrough leads to thrown exception.
INT_VACUOUS_BIT_OPERATION: bit operations that don't do any meaningful work.
FB_UNEXPECTED_WARNING: warning generated that conflicts with @NoWarning FindBugs annotation.
FB_MISSING_EXPECTED_WARNING: warning not generated despite presence of @ExpectedWarning FindBugs annotation.
NOISE category: intended for use in data mining experiments.

NOISE_NULL_DEREFERENCE: fake null point dereference warning.
NOISE_METHOD_CALL: fake method call warning.
NOISE_FIELD_REFERENCE: fake field dereference warning.
NOISE_OPERATION: fake operation warning.

Other:

Garvin Leclaire has created a new Apache Maven repository for FindBugs at the Google Code FindBugs SVN repository. (Thanks Garvin!)

Fixes:

[ 2317842 ] Highlighting broken in Windows
[ 2515908 ] check for oddness should track sign of argument
[ 2487936 ] "L B GC" false pos cast from Map.Entry.getKey() to Map.get()
[ 2528264 ] Ant tasks not compatible with Ant 1.7.1
[ 2539590 ] SF_SWITCH_FALLTHROUGH wrong message reported
[ 2020066 ] Bug history displayed in fancy-hist.xsl is incorrect
[ 2545098 ] Invalid character in analysis results file
[ 2492673 ] Plugin sites should specify 'requires Eclipse 3.3 or newer'
[ 2588044 ] a tiny typing error
[ 2589048 ] Documentation for convertXmlToText insufficient
[ 2638739 ] NullPointerException when building

Patches:

[ 2538184 ] Make BugCollection implement Iterable<BugInstance> (thanks to Tomas Pollak)
[ 2249771 ] Add Maven2 Findbugs plugin link to the Links page (thanks to Garvin Leclaire)
[ 2609526 ] Japanese manual update (thanks to K. Hashimoto)
[ 2119482 ] CheckBcel checks for nonexistent classes (thanks to Jerry James)

FindBugs Eclipse plugin:

Major feature enhancements (thanks to Andrei Loskutov). See this overview for more information.
Major test improvements (thanks to Tomas Pollak).
Fixes:

[ 2532365 ] Compiler warning
[ 2522989 ] Fix filter files selection
[ 2504068 ] NullPointerException
[ 2640849 ] NPE in Eclipse plugin 1.3.7 and Eclipse 3.5 M5

Patches:

[ 2143140 ] Unchecked conversion fixes for Eclipse plugin (thanks to Jerry James)

Older versions...

Talks about FindBugs

Mistakes That Matter, JavaOne, 2009

Quicktime movie showing of demo of our new GUI to view some of the null pointer bugs in Eclipse (Big file warning: 23 Megabytes)
JavaOne 2007 talk on Improving Software Quality Using Static Analysis
Talk Bill Pugh gave at SD Best Practices, Sept 14th (more of a handle on tutorial about using FindBugs)
Talk Bill Pugh gave at ITA Software and MIT, Sept 12th and 13th (more of a research focus)
Video of talk Bill Pugh gave at Google, July 6th, 2006
Java Posse podcast interview with Bill Pugh and Brian Goetz

Papers about FindBugs

Finding More Null Pointer Bugs, But Not Too Many, by David Hovemeyer, York College of Pennsylvania and William Pugh, Univ. of Maryland, 7th ACM SIGPLAN-SIGSOFT Workshop on Program Analysis for Software Tools and Engineering, June, 2007
Evaluating Static Analysis Defect Warnings On Production Software, Nathaniel Ayewah and William Pugh, Univ. of Maryland, and J. David Morgenthaler, John Penix and YuQian Zhou, Google, Inc., 7th ACM SIGPLAN-SIGSOFT Workshop on Program Analysis for Software Tools and Engineering, June, 2007

Additional Support

YourKit is kindly supporting open source projects with its full-featured Java Profiler. YourKit, LLC is creator of innovative and intelligent tools for profiling Java and .NET applications. Take a look at YourKit's leading software products: YourKit Java Profiler and YourKit .NET Profiler.

The FindBugs project also uses FishEye and Clover, which are generously provided by Cenqua/Atlassian.

Additional financial support for the FindBugs project has been provided by Google, Sun Microsystems, National Science Foundation grants ASC9720199 and CCR-0098162, Fortify Software, SureLogic, and by a 2004 IBM Eclipse Innovation award.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

Send comments to findbugs@cs.umd.edu