问题
I'm trying to port mustache.scala to scala 2.10, and make it built with maven with antlr3-maven-plugin instead of sbt. so far, i got this, and the code is compiled successfully. but at runtime, when i try to execute something simple like new Mustach("hello {{world}}!"), i get a java.lang.NoClassDefFoundError.
the weird thing, is that at first, i got the NoClassDefFoundError for Node class. i didn't understand why the java classes were'nt in the compiled jar, but i was eager to test if it worked. so i compiled just the two java classes with javac, and invoked the scala REPL as follows:
$scala -cp path/to/compiled/java/classes:path/to/jar-with-dependencies.jar
Welcome to Scala version 2.10.2 (OpenJDK 64-Bit Server VM, Java 1.7.0_21).
Type in expressions to have them evaluated.
Type :help for more information.
scala> import org.monkey.mustache._
import org.monkey.mustache._
scala> new Mustache("hello {{world}}!")
java.lang.NoClassDefFoundError: org/monkey/mustache/MustacheLexer
at org.monkey.mustache.Mustache.<init>(Mustache.scala:21)
at org.monkey.mustache.Mustache.<init>(Mustache.scala:32)
at .<init>(<console>:11)
at .<clinit>(<console>)
at .<init>(<console>:7)
at .<clinit>(<console>)
at $print(<console>)
...
so now i'm getting a NoClassDefFoundError on ANTLR output classes, so I see that not only the java files compile output was not packaged in the jar, but also ANTLR generated files. the scala code is depended on the java code as well as on the ANTLR generated code, so if the compilation succeeds, it must mean that at some point the java & ANTLR code was compiled succefully.
the relevant maven output is attached:
$ mvn clean install
.
. irrelevant output omitted...
.
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building mustache_2.10 1.0.5-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.3:clean (default-clean) @ mustache_2.10 ---
[INFO] Deleting file set: /path/to/mustache.scala/target (included: [**], excluded: [])
[INFO]
[INFO] --- antlr3-maven-plugin:1.0:antlr (default) @ mustache_2.10 ---
[INFO] Processing grammar /path/to/mustache.scala/src/main/antlr/org/monkey/mustache/Mustache.g
[INFO]
[INFO] --- maven-resources-plugin:2.3:resources (default-resources) @ mustache_2.10 ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /path/to/mustache.scala/src/main/resources
[INFO]
[INFO] --- scala-maven-plugin:3.1.3:compile (project-resources-execution) @ mustache_2.10 ---
[INFO] /path/to/mustache.scala/src/main/java:-1: info: compiling
[INFO] /path/to/mustache.scala/target/generated-sources/antlr:-1: info: compiling
[INFO] /path/to/mustache.scala/src/main/scala:-1: info: compiling
[INFO] Compiling 8 source files to /path/to/mustache.scala/target/classes at 1371141939993
[INFO] prepare-compile in 0 s
[INFO] compile in 8 s
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ mustache_2.10 ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default) @ mustache_2.10 ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- scala-maven-plugin:3.1.3:compile (compile) @ mustache_2.10 ---
[INFO] /path/to/mustache.scala/src/main/java:-1: info: compiling
[INFO] /path/to/mustache.scala/target/generated-sources/antlr:-1: info: compiling
[INFO] /path/to/mustache.scala/src/main/scala:-1: info: compiling
[INFO] Compiling 8 source files to /path/to/mustache.scala/target/classes at 1371141948773
[INFO] prepare-compile in 0 s
[INFO] compile in 8 s
[INFO]
.
. irrelevant output omitted...
.
[INFO]
[INFO] --- maven-jar-plugin:2.2:jar (default-jar) @ mustache_2.10 ---
[INFO] Building jar: /path/to/mustache.scala/target/mustache_2.10-1.0.5-SNAPSHOT.jar
[INFO]
[INFO] >>> maven-source-plugin:2.2.1:jar (attach-sources) @ mustache_2.10 >>>
[INFO]
[INFO] --- antlr3-maven-plugin:1.0:antlr (default) @ mustache_2.10 ---
[INFO] No grammars processed; generated files are up to date
[INFO]
[INFO] <<< maven-source-plugin:2.2.1:jar (attach-sources) @ mustache_2.10 <<<
[INFO]
[INFO] --- maven-source-plugin:2.2.1:jar (attach-sources) @ mustache_2.10 ---
[INFO] Building jar: /path/to/mustache.scala/target/mustache_2.10-1.0.5-SNAPSHOT-sources.jar
[INFO]
[INFO] --- maven-install-plugin:2.3:install (default-install) @ mustache_2.10 ---
[INFO] Installing /path/to/mustache.scala/target/mustache_2.10-1.0.5-SNAPSHOT.jar to /path/to/mustache_2.10/1.0.5-SNAPSHOT/mustache_2.10-1.0.5-SNAPSHOT.jar
[INFO] Installing /path/to/mustache.scala/pom.xml to /path/to/.m2/repository/org/monkey/mustache_2.10/1.0.5-SNAPSHOT/mustache_2.10-1.0.5-SNAPSHOT.pom
[INFO] Installing /path/to/mustache.scala/target/mustache_2.10-1.0.5-SNAPSHOT-sources.jar to /path/to/.m2/repository/org/monkey/mustache_2.10/1.0.5-SNAPSHOT/mustache_2.10-1.0.5-SNAPSHOT-sources.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 29.516s
[INFO] Finished at: Thu Jun 13 19:46:06 IDT 2013
[INFO] Final Memory: 16M/214M
[INFO] ------------------------------------------------------------------------
buttom line, how do i get the compiled output from java files to be packaged in the jar along with the compiled scala code?
回答1:
The scala compiler read the source *.java (explicit in your log), but it doesn't compile them. To compile your *.scala it can used *.java OR *.class.
The classes generated into target/generated-sources/antlr don't exist into target/classes. The compilation is not done by maven-compiler-plugin. Wrong use of includes : it's a filter not a way to add sources dir. Try to remove it : you will have compilation error like
.../MustacheLexer.java:[168,17] cannot find symbol
[ERROR] symbol : variable type
Sorry I don't know/search how to fix it.
来源：https://stackoverflow.com/questions/17092892/building-a-scala-java-antlr-project-in-maven-results-with-classdefnotfounderror