Javac 不会将类编译到目标文件夹

Question

是的，我做到了mvn clean。

在 Maven 3.1.0、3.0.4 和 3.0.3 中尝试过

我的多模块 maven 项目的构建 (mvn install) 在某些模块处失败。原因是最后一个模块是用SUCCESS构建的，但实际上jar是空的。然后下一个模块找不到它需要查看的类。

[INFO] Reactor Summary:
[INFO] 
[INFO] myproject ......................................... SUCCESS [0.309s]
[INFO] myproject-service ................................. SUCCESS [0.011s]
[INFO] myproject-service-api ............................ SUCCESS [1.242s]
[INFO] myproject-service-spi ............................ FAILURE [1.422s]
[INFO] myproject-datap-lib-impl .................. SKIPPED
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 19.746s
[INFO] Finished at: Wed Jul 24 17:30:57 EEST 2013
[INFO] Final Memory: 62M/919M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (default-compile) on project myproject-service-spi: Compilation failure: Compilation failure:
[ERROR] C:\dev\mything\myproject\trunk-checkout2\service\spi\src\main\java\org\myself\service\spi\validation\fake\AbstractConfigurableFakeDetector.java:[12,55] error: package org.myself.service.validation.fake does not exist

这是运行mvn -X clean install -amd -Dmaven.test.skip=true > build.loghttp://nopaste.info/7f07571993.html的完整调试输出

在 IntelliJ IDEA 中一切看起来都不错，类存在。

不仅生成的jar是空的，文件夹service/api/target/classes也是。

我的 service-api 的 pom 文件非常基本，就像其他工作一样：

<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
         xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>myparent</artifactId>
        <groupId>my.parent</groupId>
        <version>myversion</version>
    </parent>

    <groupId>myproject.service.api</groupId>
    <artifactId>myproject-service-api</artifactId>

    <dependencies>
        ... some local and external dependencies
    </dependencies>

    <properties>
    </properties>
</project>

这里没有 maven 插件。

我认为我没有循环依赖，因为 Maven 3 会检测到这一点。

更新

我现在明白了这一点：在创建空 jar 的模块上进行简单的 mvn 编译，在 IntelliJ IDEA 中为我提供了以下输出：

[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building myproject-service-api 4.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ myproject-service-api ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory C:\myproject\trunk-checkout2\service\api\src\main\resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ myproject-service-api ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 217 source files to C:\myproject\trunk-checkout2\service\api\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.908s
[INFO] Finished at: Wed Jul 24 21:56:49 EEST 2013
[INFO] Final Memory: 20M/232M
[INFO] ------------------------------------------------------------------------

在运行之后，文件夹 C:\myproject\trunk-checkout2\service\api\target\classes 是空的。所以检测到 217 个 Java 类，maven 说它会编译它们并将它们放入我的目标文件夹，但它没有。

更新 2

我已经比较了一个模块的mvn -X compile 的输出与这个模块相比（请记住，所有模块都以 BUILD SUCCESS 结尾，但这个模块有一个空的目标文件夹）。有一个区别：失败的文件将所有 java 文件列为“Stale source detected”。

[DEBUG] Using compiler 'javac'.
[DEBUG] Source directories: [C:\myproject\trunk-checkout2\service\api\src\main\java]
[DEBUG] Classpath: [C:\myproject\trunk-checkout2\service\api\target\classes
... all the dependency jars
[DEBUG] Output directory: C:\myproject\trunk-checkout2\service\api\target\classes
[DEBUG] CompilerReuseStrategy: reuseCreated
[DEBUG] useIncrementalCompilation enabled
[DEBUG] Stale source detected: C:\dev\myproject\trunk-checkout2\service\api\src\main\java\my\Class.java
... listing all 217 classes
[INFO] Changes detected - recompiling the module!
[DEBUG] Classpath:
[DEBUG]  C:\myproject\trunk-checkout2\service\api\target\classes
... all the dependency jars
[DEBUG] Source roots:
[DEBUG]  C:\myproject\trunk-checkout2\service\api\src\main\java
[DEBUG] Command line options:
[DEBUG] -d (...) -g -nowarn -target 1.6 -source 1.6 -encoding UTF-8
[DEBUG] incrementalBuildHelper#beforeRebuildExecution
[INFO] Compiling 217 source files to C:\myproject\trunk-checkout2\service\api\target\classes
[DEBUG] incrementalBuildHelper#afterRebuildExecution
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.060s
[INFO] Finished at: Wed Jul 24 23:16:37 EEST 2013
[INFO] Final Memory: 22M/328M
[INFO] ------------------------------------------------------------------------

我已经看到这个错误报告https://jira.codehaus.org/browse/MCOMPILER-205 并且我确实在这个模块中有 package-info.java 文件，但是我尝试了一个 pre-3 编译器插件，结果相同。而且我已经尝试过那里描述的注释，也没有运气。所以我认为情况并非如此。

我没有 public static void main，因此这个 bug Workaround for javac compilation order bug in maven 不可能。

更新 3

javac 中止，没有通知（-verbose 开启）。仅 1 节课有效，所有 217 节课均失败。所以我想我必须尝试找出导致它的原因，等等......会再次发布。

Answer 1

首先在您的日志输出中，有几个关于 ${version} 之类的提示，您应该修复这些提示，此外还有其他关于依赖项重复定义等的警告。

我已经更深入地查看了日志输出：

[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespivalidationfakeAbstractConfigurableFakeDetector.java:[12,55] error: package org.myself.service.validation.fake does not exist
[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespivalidationfakeAbstractConfigurableFakeDetector.java:[13,55] error: package org.myself.service.validation.fake does not exist
[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespivalidationfakeAbstractConfigurableFakeDetector.java:[82,14] error: cannot find symbol
[ERROR]  symbol:  class SimpleValidationResult
  location: class AbstractConfigurableFakeDetector
C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespivalidationfakeAbstractConfigurableFakeDetector.java:[106,66] error: cannot find symbol
[ERROR]  symbol:  class FakeType
  location: class AbstractConfigurableFakeDetector
C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespivalidationfakeAbstractConfigurableFakeDetector.java:[97,8] error: cannot find symbol
[ERROR]  symbol:  class SimpleValidationResult
  location: interface SomethingThatReturnsValidationResult
C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespigenderresultAverageComputedGenderResultCollector.java:[4,46] error: package org.myself.service.gender does not exist
[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespigenderresultAverageComputedGenderResultCollector.java:[5,46] error: package org.myself.service.gender does not exist
[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespigenderresultAbstractAverageGenderCollector.java:[4,46] error: package org.myself.service.gender does not exist
[ERROR] C:devmythingmyprojecttrunk-checkout2servicespisrcmainjavaorgmyselfservicespigenderresultAverageComputedGenderResultCollector.java:[31,29] error: cannot find symbol
[ERROR]  symbol:  class ComputedGenderResult
  location: class AverageComputedGenderResultCollector 

这给我的印象是您正在使用测试类，或者可能是来自测试区域的包名称，这将不起作用，或者您缺少对其他包的依赖。

Answer 2

原因是由于 javac 中的错误。它无法处理的一些有效语法。然后生成空罐子，依此类推。