[java] Getting ClassNotFoundException on standard PMD cyclomatic complexity plug-in

[MrAngry52]

Affects PMD Version:
6.20.0
Rule:
category/java/design.xml/CyclomaticComplexity
Description:
Using a simple .java file (code below) I was attempting to use the cyclomatic complexity functionality of the design rule and received no result. Running pmd with the -debug option showed the following logging information (where CCExample.java was the file in question):

Command run:

pmd -d CCExample.java -debug -R category/java/design.xml/CyclomaticComplexity -f text

Output:

Jan 15, 2020 2:35:58 PM net.sourceforge.pmd.RulesetsFactoryUtils printRuleNamesInDebug
FINER: Loaded rule CyclomaticComplexity
Jan 15, 2020 2:35:58 PM net.sourceforge.pmd.processor.PmdRunnable call
FINE: Processing C:\Temp\CCExample.java
Jan 15, 2020 2:35:58 PM net.sourceforge.pmd.lang.java.typeresolution.ClassTypeResolver visit
FINE: Could not find class CCExample, due to: java.lang.ClassNotFoundException: CCExample

Code Sample demonstrating the issue:

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class CCExample
{
    public static String reduceString(String s, int index)
    {
        int lastIndex = s.length() - 1;

        if (s.length() == 0)
        {
            return "Empty String";
        }
        else if (index >= lastIndex)
        {
            if (isReduced(s, 0))
            {
                return s;
            }
            else
            {
                return reduceString(s, 0);
            }
        }
        else if (s.charAt(index) == s.charAt(index + 1))
        {
            if (index + 1 < lastIndex)
            {
                return reduceString(s.substring(0, index) + s.substring(index + 2, s.length()), index);
            }
            else
            {
                return reduceString(s.substring(0, index), index);
            }
        }
        else
        {
            return reduceString(s, index + 1);
        }
    }

    public static boolean isReduced(String s, int index)
    {
        int lastIndex = s.length() - 1;

        if (index == lastIndex || s.length() == 0)
        {
            return true;
        }
        else if (s.charAt(index) != s.charAt(index + 1))
        {
            return isReduced(s, index + 1);
        }
        else
        {
            return false;
        }
    }

    public static void main(final String[] args)
    {
        if (args.length != 1)
        {
            System.out.println("Usage: java CCExample <string>");
        }
        else
        {
            final String s = args[0];
            System.out.println(reduceString(s, 0));
        }
    }
}

Running PMD through: [CLI]

Windows 10
Java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)

[oowekyala]

The ClassNotFoundException can be ignored, this rule doesn't need type information.

What happens here is simply that your code is not complex enough to trigger a violation. The rule by default reports methods that have a cyclo over 10. The first method has cyclo 6, the second 4, the main 3.

Refer to the doc of the rule, which mentions the following snippet if you want to customize the report threshold:

<rule ref="category/java/design.xml/CyclomaticComplexity">
    <properties>
        <property name="classReportLevel" value="80" />
        <property name="methodReportLevel" value="10" />
        <property name="cycloOptions" value="" />
    </properties>
</rule>

[MrAngry52]

Fair enough, thank you for the explanation. It was the ClassNotFoundException that threw me, when I saw that I figured it was a parsing error versus it being below a minimum threshold. From: Clément Fournier <[email protected]> Sent: Wednesday, January 15, 2020 5:57 PM To: pmd/pmd <[email protected]> Cc: MrAngry52 <[email protected]>; Author <[email protected]> Subject: Re: [pmd/pmd] [java] Getting ClassNotFoundException on standard PMD cyclomatic complexity plug-in (#2229) The ClassNotFoundException can be ignored, this rule doesn't need type information. What happens here is simply that your code is not complex enough to trigger a violation. The rule by default reports methods that have a cyclo over 10. The first method has cyclo 6, the second 4, the main 3. Refer to the doc of the rule<https://pmd.github.io/latest/pmd_rules_java_design.html#cyclomaticcomplexity>, which mentions the following snippet if you want to customize the report threshold: <rule ref="category/java/design.xml/CyclomaticComplexity"> <properties> <property name="classReportLevel" value="80" /> <property name="methodReportLevel" value="10" /> <property name="cycloOptions" value="" /> </properties> </rule> — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#2229?email_source=notifications&email_token=AHFCVEX6GJXMVGAREVMKJVLQ565IPA5CNFSM4KHMODZ2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEJCPLBQ#issuecomment-574944646>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AHFCVEU52DVW5DOGQ6EW6M3Q565IPANCNFSM4KHMODZQ>.