我需要将 Apple 推送通知服务集成到 Openfire。
为此，我关注了openfire-apns-plugin。但是当我执行mvn clean install命令（最后一步）时，我得到了错误。所以，因为openfire-apns.jar没有创建。
请帮我弄清楚这个问题。
执行后生成以下日志mvn clean install，
root@vps [~/openfire_src/openfire-apns-plugin]# mvn clean install
[INFO] Scanning for projects...
[INFO]
[INFO] Using the builder org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder with a thread count of 1
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building APNS Service 1.0.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ apns ---
[INFO] Deleting /root/openfire_src/openfire-apns-plugin/target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ apns ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /root/openfire_src/openfire-apns-plugin/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.0:compile (default-compile) @ apns ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 4 source files to /root/openfire_src/openfire-apns-plugin/target/classes
[INFO]
[INFO] --- maven-openfire-plugin:1.0.2-SNAPSHOT:jspc (default-jspc) @ apns ---
[INFO] Logging to org.slf4j.impl.SimpleLogger(org.mortbay.log) via org.mortbay.log.Slf4jLog
java.lang.NullPointerException: charsetName
at java.io.OutputStreamWriter.<init>(OutputStreamWriter.java:99)
at org.apache.jasper.compiler.JDTJavaCompiler.getJavaWriter(JDTJavaCompiler.java:120)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:146)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:362)
at org.apache.jasper.JspC.processFile(JspC.java:1137)
at org.apache.jasper.JspC.execute(JspC.java:1306)
at com.reucon.maven.plugin.openfire.jspc.JspcMojo.compile(JspcMojo.java:279)
at com.reucon.maven.plugin.openfire.jspc.JspcMojo.execute(JspcMojo.java:196)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:133)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
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:108)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:76)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:116)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:361)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:155)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:584)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:213)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:157)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.557 s
[INFO] Finished at: 2014-09-15T06:01:37-05:00
[INFO] Final Memory: 17M/98M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.reucon.maven.plugins:maven-openfire-plugin:1.0.2-SNAPSHOT:jspc (default-jspc) on project apns: Failure processing jsps -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[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/MojoFailureException