JCommander#parseValues throws NullPointerException (since 1.71)

During the changes in commit 4435722a0b45be660b1b58834d4f5326fc78c9ad new defect has crept in which raises a NullPointerException.

Exception in thread "main" java.lang.NullPointerException
	at com.beust.jcommander.JCommander.parseValues(JCommander.java:718)
	at com.beust.jcommander.JCommander.parse(JCommander.java:340)
	at com.beust.jcommander.JCommander.parseWithoutValidation(JCommander.java:330)

The Boolean in line 717 Boolean value = (Boolean) pd.getParameterized().get(pd.getObject()); can be null if no default value is present for a Boolean parameter like:

@Parameter(names = {"--flag"}, description = "Just a simple flag")
private Boolean simpleFlag;

This behaviour is not obvious because strings can be null. And a nullable parameter is important if one just wants to override a configured value with those of the command line if they are present.

[glhez]

@cbeust The problem is still there using version from maven central. I don’t know how to publish a new version to central and perhaps it is a task that fall on you being main maintainer 😃 (beside if I use ./kobaltw clean compîle publishToMavenLocal on WIndows, it fails with java.lang.IllegalArgumentException: Illegal character in opaque part at index 11: jar:file:E:\git\github\jcommander\.\kobaltBuild\ => you might need to use Path.toURI() or File.toURI() …) Nonetheless, my fix fix your problem @bisoldi .

[bisoldi]

Unfortunately, it does not work for me. Using v1.72, I still get a NullPointerException, however as soon as I switched the dependency to v1.69, it worked fine. Below is the test class I used.

package com.myapp.models;

import com.beust.jcommander.JCommander;
import com.beust.jcommander.Parameter;
import org.junit.Test;

public class CmdLineArgsTest {
    
    class CmdLineArgs {

        @Parameter(names = {"--help", "-h"}, description = "Display help for this application", help = true)
        private Boolean help;

        @Parameter(names = {"--topic", "-t"}, description = "Sets a single topic (can be multiple words) for the processing of the articles")
        private String topic;

        public Boolean getHelp() {
            return help;
        }

        public void setHelp(Boolean help) {
            this.help = help;
        }

        public String getTopic() {
            return topic;
        }

        public void setTopic(String topic) {
            this.topic = topic;
        }
    }

    @Test
    public void testCmdLineArgs() {

        CmdLineArgs cmdLine = new CmdLineArgs();

        JCommander jcmd = JCommander.newBuilder()
                .addObject(cmdLine)
                .build();

        jcmd.parse(new String[]{"-h"});

        if (cmdLine.getHelp()) {
            System.out.println("help");
            System.exit(0);
        }
    }

}

Here is the full stack trace:

java.lang.NullPointerException
	at com.beust.jcommander.JCommander.parseValues(JCommander.java:718)
	at com.beust.jcommander.JCommander.parse(JCommander.java:340)
	at com.beust.jcommander.JCommander.parse(JCommander.java:319)
	at com.myapp.models.CmdLineArgsTest.testCmdLineArgs(CmdLineArgsTest.java:43)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
	at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
	at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)