Falko Modler created CXF-7083:
---------------------------------
Summary: Maven Plugins: System properties handling in
ClassLoaderSwitcher breaks thread safety
Key: CXF-7083
URL: https://issues.apache.org/jira/browse/CXF-7083
Project: CXF
Issue Type: Bug
Components: Tooling
Affects Versions: 2.7.18
Environment: Apache Maven 3.3.9
(bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T17:41:47+01:00)
Maven home: /usr/maven/default
Java version: 1.8.0_102, vendor: Oracle Corporation
Java home: /usr/java/jdk1.8.0_102/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "2.6.32-431.29.2.el6.x86_64", arch: "amd64", family:
"unix"
Reporter: Falko Modler
We got a rather large Maven project with a couble of modules that execute
{{cxf-codegen-plugin}}. Our builds runs in parallel mode via {{-Tx}} and
according to the JavaDoc in the plugin should be fine with that:
{code:java|title=https://github.com/apache/cxf/blob/cxf-2.7.18/maven-plugins/codegen-plugin/src/main/java/org/apache/cxf/maven_plugin/wsdl2java/WSDL2JavaMojo.java}
/**
* @goal wsdl2java
* @phase generate-sources
* @description CXF WSDL To Java Tool
* @requiresDependencyResolution test
* @threadSafe
*/
public class WSDL2JavaMojo extends AbstractCodegenMoho {
...
{code}
But from time to time (maybe 5% of our builds) we see following exception
causing the respective build to fail:
{noformat}
[ERROR] Failed to execute goal
org.apache.cxf:cxf-codegen-plugin:2.7.18:wsdl2java (exampleExec) on project
example-module: Execution patientenService of goal
org.apache.cxf:cxf-codegen-plugin:2.7.18:wsdl2java failed.
ConcurrentModificationException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal
org.apache.cxf:cxf-codegen-plugin:2.7.18:wsdl2java (patientenService) on
project middleware-service-patient: Execution patientenService of goal
org.apache.cxf:cxf-codegen-plugin:2.7.18:wsdl2java failed.
at
org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
at
org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at
org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at
org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at
org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call(MultiThreadedBuilder.java:185)
at
org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call(MultiThreadedBuilder.java:181)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at
java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution
patientenService of goal org.apache.cxf:cxf-codegen-plugin:2.7.18:wsdl2java
failed.
at
org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:145)
at
org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
... 11 more
Caused by: java.util.ConcurrentModificationException
at java.util.Hashtable$Enumerator.next(Hashtable.java:1378)
at java.util.HashMap.putMapEntries(HashMap.java:511)
at java.util.HashMap.<init>(HashMap.java:489)
at
org.apache.cxf.maven_plugin.ClassLoaderSwitcher.restoreClassLoader(ClassLoaderSwitcher.java:129)
at
org.apache.cxf.maven_plugin.AbstractCodegenMoho.execute(AbstractCodegenMoho.java:326)
at
org.apache.cxf.maven_plugin.wsdl2java.WSDL2JavaMojo.execute(WSDL2JavaMojo.java:524)
at
org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
... 12 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please
read the following articles:
[ERROR] [Help 1]
http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException
{noformat}
There seems to be a write access from another thread while
{{ClassLoaderSwitcher}} tries to copy the system properties:
{code:java|title=https://github.com/apache/cxf/blob/cxf-2.7.18/maven-plugins/wadl2java-plugin/src/main/java/org/apache/cxf/maven_plugin/common/ClassLoaderSwitcher.java#L131}
if (origProps != null) {
Map<Object, Object> newProps = new HashMap<Object,
Object>(System.getProperties());
for (Object o : newProps.keySet()) {
if (!origProps.containsKey(o)) {
System.clearProperty(o.toString());
}
}
System.getProperties().putAll(origProps);
}
{code}
*Possible solutions*:
- synchronize on {{System.getProperties()}} in the entire block (lines 129-135)
- create a clone
{code:java}
(Properties) System.getProperties().clone()
{code}
and instead of {{.putAll()}} use {{.setProperties(...)}}
I haven't checked {{ClassLoaderSwitcher .switchClassLoader()}} but I guess
something similar needs to be done there.
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