Detect bugs from Java code using FindBugs

Scariest: ranked between 1 & 4.

Scary: ranked between 5 & 9.

Troubling: ranked between 10 & 14.

Of concern: ranked between 15 & 20.

While the bug rank describes severity, the confidence factor reflects the likelihood of these bugs to be flagged as real ones. The confidence was originally called priority, but it was renamed in the new version.
Of course, some defects can be open to interpretation, and they can even exist without causing any harm to the desired behavior of a software. That's why, in a real-world situation, we need to properly configure static analysis tools by choosing a limited set of defects to activate in a specific project.

FindBugs plugin makes it easy to customize the bugs analysis strategy, by offering various ways to filter warning and limit the strictness of the results. You can check the configuration interface by going to Window -> Preferences -> Java -> FindBugs:

You can freely uncheck unwanted categories, raise the minimum rank to report, specify the minimum confidence to report, and customize markers for bugs ranks – Warning, Info, or Error.
FindBugs divide defects in many categories:

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  Correctness – gathers general bugs, e.g. infinite loops, inappropriate use of equals(), etc
  
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  Bad practice, e.g. exceptions handling, opened streams, Strings comparison, etc
  
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  Performance, e.g. idle objects
  
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  Multithreaded correctness – gathers synchronization inconsistencies and various problems in a multi-threaded environment
  
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  Internationalization – gathers problems related to encoding and application's internationalization
  
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  Malicious code vulnerability – gathers vulnerabilities in code, e.g. code snippets that can be exploited by potential attackers
  
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  Security – gathers security holes related to specific protocols or SQL injections
  
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