SpotBugs Guide

SpotBugs is an open-source static code analysis tool used in software development for bug detection. It scans bytecode (i.e., .class files) in your Java applications for bug patterns and ranks potential issues in terms of severity. SpotBugs can identify a variety of common coding mistakes, including null pointer dereferences, infinite recursive loops, bad uses of the Java libraries, and more.

SpotBugs is the spiritual successor of FindBugs, another well-known static analysis tool for Java. After the last FindBugs release in 2015, the project was effectively discontinued, and SpotBugs was created to continue the work.

SpotBugs can be used standalone or integrated into IDEs like Eclipse, IntelliJ, and NetBeans. It also has plugins for build tools like Maven and Gradle.

To use SpotBugs with Maven, you need to add the spotbugs-maven-plugin to your pom.xml file. Here's how you can do it:

Add the plugin into your pom.xml like below:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>com.github.spotbugs</groupId>
        <artifactId>spotbugs-maven-plugin</artifactId>
        <version>4.7.2.1</version>
        <configuration>
          <effort>Max</effort>
          <threshold>Low</threshold>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>com.github.spotbugs</groupId>
            <artifactId>spotbugs</artifactId>
            <version>4.7.3</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

In this configuration:

• The effort option controls how much effort SpotBugs puts into bug detection. The options are Min, Default, and Max. Higher effort levels will find more bugs but will take more time.
• The threshold option controls the minimum rank of bugs to report. The options are Low, Medium, and High. Lower thresholds will report more bugs, including those that are less likely to be real problems.

In the example above, SpotBugs is configured to put maximum effort into bug detection and report all bugs it finds, including those of low rank. Adjust these options as needed for your project.

Now. Create a Java class to check. here is a simple Java class with a potential null pointer dereference bug:

public class BugExample {
    private String name;

    public void setName(String name) {
        this.name = name;
    }

    public int getNameLength() {
        return name.length();
    }

    public static void main(String[] args) {
        BugExample example = new BugExample();
        System.out.println(example.getNameLength());
    }
}

Then:

1. Build project
2. Open Maven sidebar --> Click the plugin bar --> Click the spotbugs menu --> Click spotbugs:spotbugs option. Wait the target/spotbugsXml.xml file be created --> Click spotbugs:gui option.

The details can be viewed in the gui interface.

reference material:
Using the SpotBugs Maven Plugin