I have a maven-based GWT project that includes Guava. I am running into trouble with Maven trying (and failing) to compile the sources that it finds in guava-gwt*.jar:
could not parse error message: symbol: static setCountImpl
location: class
/home/mark/.m2/repository/com/google/guava/guava-gwt/11.0.1/guava-gwt-11.0.1.jar(com/google/common/collect/AbstractMultiset.java):100: error: cannot find symbol
return setCountImpl(this, element, count);
^
I can’t figure out why Maven thinks it needs to compile the sources in guava-gwt. Here’s what my project looks like:
├── pom.xml
└── src
├── main
│ └── java
└── test
└── java
└── SomeTestFile.java
SomeTestFile.java
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import org.junit.Test;
public class SomeTestFile {
@Test
public void testMethod() {
Multimap<Integer, String> someMap = ArrayListMultimap.create();
someMap.put(5, "five");
System.out.println(someMap);
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>guava-problem</groupId>
<artifactId>guava-problem</artifactId>
<version>1.0</version>
<dependencies>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>11.0.1</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava-gwt</artifactId>
<version>11.0.1</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.8.2</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
I have already tried the following:
- Removing the
guavadependency (leaving onlyguava-gwt) - Scoping
guava-gwttoprovided
I’m not sure what else to try. guava-gwt includes sources because GWT will compile it into equivalent Javascript. But I don’t want Maven to try to compile these sources.
Edit
Just a note…the test files themselves have no real need for guava-gwt over guava since they are compiled and run as Java code (they don’t go through the GWT compile step). I don’t need guava-gwt specifically for these tests but it needs to be available for my actual GWT client code.
Full Maven Output
mark@mark-peters:~/devel/guava-problem$ mvn -V clean test-compile
Apache Maven 2.2.1 (rdebian-1)
Java version: 1.7.0
Java home: /usr/lib/jvm/jdk1.7.0/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux" version: "2.6.32-38-generic" arch: "amd64" Family: "unix"
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - guava-problem:guava-problem:jar:1.0
[INFO] task-segment: [clean, test-compile]
[INFO] ------------------------------------------------------------------------
[INFO] [clean:clean {execution: default-clean}]
[INFO] Deleting file set: /home/mark/devel/guava-problem/target (included: [**], excluded: [])
[INFO] [resources:resources {execution: default-resources}]
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/mark/devel/guava-problem/src/main/resources
[INFO] [compiler:compile {execution: default-compile}]
[INFO] Nothing to compile - all classes are up to date
[INFO] [resources:testResources {execution: default-testResources}]
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/mark/devel/guava-problem/src/test/resources
[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Compiling 1 source file to /home/mark/devel/guava-problem/target/test-classes
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Compilation failure
/home/mark/.m2/repository/com/google/guava/guava-gwt/11.0.1/guava-gwt-11.0.1.jar(com/google/common/collect/AbstractMultiset.java):[19,0] error: cannot find symbol
could not parse error message: symbol: static setCountImpl
location: class
/home/mark/.m2/repository/com/google/guava/guava-gwt/11.0.1/guava-gwt-11.0.1.jar(com/google/common/collect/AbstractMultiset.java):100: error: cannot find symbol
return setCountImpl(this, element, count);
^
could not parse error message: symbol: method setCountImpl(AbstractMultiset<E>,E,int)
location: class AbstractMultiset<E>
where E is a type-variable:
E extends Object declared in class AbstractMultiset
/home/mark/.m2/repository/com/google/guava/guava-gwt/11.0.1/guava-gwt-11.0.1.jar(com/google/common/collect/AbstractMultiset.java):105: error: cannot find symbol
return setCountImpl(this, element, oldCount, newCount);
^
[INFO] ------------------------------------------------------------------------
[INFO] For more information, run Maven with the -e switch
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2 seconds
[INFO] Finished at: Tue Feb 21 12:49:42 EST 2012
[INFO] Final Memory: 18M/212M
[INFO] ------------------------------------------------------------------------
Edit (again)
Having found that the source of the problem has nothing to do with Guava but rather the Maven version (see my answer), I’ve updated the title and question to try to be a lot more helpful to future users.
tl;dr
Maven 2 and JDK 7 are incompatible, as Maven tries to parse javac output which has changed in JDK 7.
Full explanation
Raghuram’s note that this worked for him in Maven 3+ took me down the road of exploring this not as a config problem but as an actual Maven problem. I started doing more testing and found that this problem:
So at that point it became clear to me that the “could not parse error message” errors were relevant, and the problem probably had less to do with the
guava-gwtcompilation occurring and more to do with Maven not knowing how to handle the errors properly.To test this I created a separate Maven project that has nothing to do with Guava:
pom.xml
ClassWithWarnings.java
Lo and behold, Maven tanks on this project as well when using Java 7:
With Java 6, it still reports the warnings, but can parse the Javac output and so doesn’t tank:
So it seems as if the problem was that the latest Maven 2 release doesn’t know how to parse error messages from Java 7+ javac. Maven 3 does. I still haven’t found documentation of this and am a little surprised that Maven doesn’t give a warning when it tries to compile against a JDK version that it doesn’t know how to support properly.