[jira] [Commented] (MCOMPILER-265) IllegalAccessError trying to access package-private method through public subclass (for same package) from another package

["Andreas Gudian (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MCOMPILER-265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15229776#comment-15229776 ] 

Andreas Gudian commented on MCOMPILER-265:
------------------------------------------

If I understand the comments on SO correctly, you got the same result from the maven run and from manually calling javac and java? At least that wouldn't be a surprise for me, as the default compiler implementation used by the plugin simply invokes the JVM's default compiler (which is essentially the same thing javac does).
Anyway, looking at your code snippets, I'd also say it's abug in the JDK. Did you try a JDK 9ea build, just for the fun of it?

> IllegalAccessError trying to access package-private method through public subclass (for same package) from another package 
> ---------------------------------------------------------------------------------------------------------------------------
>
>                 Key: MCOMPILER-265
>                 URL: https://issues.apache.org/jira/browse/MCOMPILER-265
>             Project: Maven Compiler Plugin
>          Issue Type: Bug
>    Affects Versions: 3.5.1
>         Environment: Eclipse Mars 4.5.1
> Maven 3.3.3
> JDK 8u31
>            Reporter: A. Di Matteo
>
> The Maven Compiler Plugin is producing an IllegalAccessError for the use case below when normal JDK compiler or Eclipse compiler would not. 
> Given the following two classes in package com.sample.package1
> {code}
> package com.sample.package1;
> abstract class Foo {
>     public String getFoo() {
>         return "foo";
>     }
> }
> {code}
> and 
> {code}
> package com.sample.package1;
> public class Bar extends Foo {
> 	public String getBar() {
> 		return "bar";
> 	}
> }
> {code}
> And the following test main in package com.sample.package2
> {code}
> package com.sample.package2;
> import java.util.stream.Stream;
> import com.sample.package1.Bar;
> public class Main {
> 	public static void main(String[] args) {
> 		System.out.println(new Bar().getFoo());
> 		// "foo"
> 		Stream.of(new Bar()).map(Bar::getFoo).forEach(System.out::println);
> 		// IllegalAccessError
> 	}
> }
> {code}
> The following scenarios occur:
> - Compiling and running the main from Eclipse > No Error
> - Compiling from console/Maven and running the main from Eclipse > Error, IllegalAccessError
> - Compiling from console/Maven and running the main via exec:java from console > Error, IllegalAccessError
> - Compiling from Eclipse and running the main via exec:java from console > No Error
> Stack trace:
> {code}
> java.lang.reflect.InvocationTargetException
> 	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:483)
> 	at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
> 	at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.IllegalAccessError: tried to access class com.sample.package1.Foo from class com.sample.package2.Main
> 	at com.sample.package2.Main.lambda$MR$main$getFoo$e8593739$1(Main.java:14)
> 	at com.sample.package2.Main$$Lambda$1/1562888899.apply(Unknown Source)
> 	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
> 	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
> 	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
> 	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
> 	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
> 	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
> 	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
> 	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
> 	at com.sample.package2.Main.main(Main.java:14)
> 	... 6 more
> {code}
> Given the following plugin configuration:
> {code}
> <plugin>
>     <groupId>org.apache.maven.plugins</groupId>
>     <artifactId>maven-compiler-plugin</artifactId>
>     <version>3.5.1</version>
>     <configuration>
>         <source>1.8</source>
>         <target>1.8</target>
>     </configuration>
> </plugin>
> {code}
> And changing it to the following:
> {code}
> <plugin>
>     <groupId>org.apache.maven.plugins</groupId>
>     <artifactId>maven-compiler-plugin</artifactId>
>     <version>3.5.1</version>
>     <configuration>
>         <source>1.8</source>
>         <target>1.8</target>
>         <compilerId>eclipse</compilerId>
>     </configuration>
>     <dependencies>
>         <dependency>
>             <groupId>org.codehaus.plexus</groupId>
>             <artifactId>plexus-compiler-eclipse</artifactId>
>             <version>2.7</version>
>         </dependency>
>     </dependencies>
> </plugin>
> {code}
> Would fix the issue, showing indeed an important difference between the Maven Compiler and the Eclipse Compiler. Which is also a difference between the JDK used and the Eclipse Compiler, hence it might be a bug in the JDK rather than a bug on the Maven Compiler Plugin.
> Further details can be found on the related StackOverflow thread:
> - http://stackoverflow.com/questions/36100552/demystifying-the-java-lang-illegalaccesserror



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