How to build vaadin/gwt-polymer-elements/demo ?

Hi All, 

I'm trying to build the demo, but I have some problems. Can anyone help?

E:\gwt-polymer-elements-master\demo>mvn clean package

[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.vaadin.polymer:gwt-polymer-elements-demo:war:1.2.3.1-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-resources-plugin is missing. @ line 118, column 21
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building gwt-polymer-elements-demo 1.2.3.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ gwt-polymer-elements-demo ---
[INFO] Deleting E:\gwt-polymer-elements-master\demo\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:copy-resources (copy-resources) @ gwt-polymer-elements-demo ---
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 4 resources
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ gwt-polymer-elements-demo ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory E:\gwt-polymer-elements-master\demo\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ gwt-polymer-elements-demo ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[INFO] Compiling 39 source files to E:\gwt-polymer-elements-master\demo\target\classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ gwt-polymer-elements-demo ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory E:\gwt-polymer-elements-master\demo\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ gwt-polymer-elements-demo ---
[INFO] No sources to compile
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ gwt-polymer-elements-demo ---
[INFO] No tests to run.
[INFO]
[INFO] --- gwt-maven-plugin:2.7.0:compile (default) @ gwt-polymer-elements-demo ---
[INFO] auto discovered modules [com.vaadin.polymer.demo.Demo]
[b][ERROR] Unknown argument: -XclosureCompiler
[ERROR] Google Web Toolkit 2.8.0-SNAPSHOT
[ERROR] Compiler [-logLevel (ERROR|WARN|INFO|TRACE|DEBUG|SPAM|ALL)] [-workDir dir] [-X[no]closureFormattedOutput] [-[no]compileReport] [-X[no]checkCasts] [-X[no]classMetadata] [-[no]draftCompile] [-[no]checkAssertions] [-XfragmentCount numFragments] [-XfragmentMerge numFragments] [-gen dir] [-[no]generateJsInteropExports] [-XmethodNameDisplayMode (NONE|ONLY_METHOD_NAME|ABBREVIATED|FULL)] [-Xnamespace (NONE|PACKAGE)] [-optimize level] [-[no]saveSource] [-setProperty name=value,value...] [-style (DETAILED|OBFUSCATED|PRETTY)] [-[no]failOnError] [-[no]validateOnly] [-sourceLevel [auto, 1.8]] [-localWorkers count] [-[no]incremental] [-war dir] [-deploy dir] [-extra dir] [-saveSourceOutput dir] module
[s][ERROR]
[ERROR] where
[ERROR]   -logLevel                      The level of logging detail: ERROR, WARN, INFO, TRACE, DEBUG, SPAM or ALL (defaults to INFO)
[ERROR]   -workDir                       The compiler's working directory for internal use (must be writeable; defaults to a system temp dir)
[ERROR]   -X[no]closureFormattedOutput   EXPERIMENTAL: Enables Javascript output suitable for post-compilation by Closure Compiler (defaults to OFF)
[ERROR]   -[no]compileReport             Compile a report that tells the "Story of Your Compile". (defaults to OFF)
[ERROR]   -X[no]checkCasts               EXPERIMENTAL: DEPRECATED: use jre.checks.checkLevel instead. (defaults to OFF)
[ERROR]   -X[no]classMetadata            EXPERIMENTAL: Include metadata for some java.lang.Class methods (e.g. getName()). (defaults to OFF)
[ERROR]   -[no]draftCompile              Compile quickly with minimal optimizations. (defaults to OFF)
[ERROR]   -[no]checkAssertions           Include assert statements in compiled output. (defaults to OFF)
[ERROR]   -XfragmentCount                EXPERIMENTAL: Limits of number of fragments using a code splitter that merges split points.
[ERROR]   -XfragmentMerge                DEPRECATED (use -XfragmentCount instead): Enables Fragment merging code splitter.
[ERROR]   -gen                           Debugging: causes normally-transient generated types to be saved in the specified directory
[ERROR]   -[no]generateJsInteropExports  Generate exports for JsInterop purposes (defaults to OFF)
[ERROR]   -XmethodNameDisplayMode        EXPERIMENTAL: Specifies method display name mode for chrome devtools: NONE, ONLY_METHOD_NAME, ABBREVIATED or FULL (defaults to NONE)
[ERROR]   -Xnamespace                    Puts most JavaScript globals into namespaces. Default: PACKAGE for -draftCompile, otherwise NONE
[ERROR]   -optimize                      Sets the optimization level used by the compiler.  0=none 9=maximum.
[ERROR]   -[no]saveSource                Enables saving source code needed by debuggers. Also see -debugDir. (defaults to OFF)
[ERROR]   -setProperty                   Set the values of a property in the form of propertyName=value1[,value2...].
[ERROR]   -style                         Script output style: DETAILED, OBFUSCATED or PRETTY (defaults to OBFUSCATED)
[ERROR]   -[no]failOnError               Fail compilation if any input file contains an error. (defaults to OFF)
[ERROR]   -[no]validateOnly              Validate all source code, but do not compile. (defaults to OFF)
[ERROR]   -sourceLevel                   Specifies Java source level (defaults to 1.8)
[ERROR]   -localWorkers                  The number of local workers to use when compiling permutations
[ERROR]   -[no]incremental               Compiles faster by reusing data from the previous compile. (defaults to OFF)
[ERROR]   -war                           The directory into which deployable output files will be written (defaults to 'war')
[ERROR]   -deploy                        The directory into which deployable but not servable output files will be written (defaults to 'WEB-INF/deploy' under the -war directory/jar, and may be the same as the -extra directory/jar)
[ERROR]   -extra                         The directory into which extra files, not intended for deployment, will be written
[ERROR]   -saveSourceOutput              Overrides where source files useful to debuggers will be written. Default: saved with extras.
[ERROR] and
[ERROR]   module[s]                      Specifies the name(s) of the module(s) to compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 5.057 s
[INFO] Finished at: 2016-07-01T14:29:47-03:00
[INFO] Final Memory: 27M/267M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:2.7.0:compile (default) on project gwt-polymer-elements-demo: Command [[
[ERROR] C:\Program Files\Java\jdk1.8.0_51\jre\bin\java -Xmx512m -classpath E:\gwt-polymer-elements-master\demo\target\classes;E:\gwt-polymer-elements-master\demo\src\main\java;C:\Users\retf\.m2\repository\com\google\gwt\gwt-user\2.8.0-SNAPSHOT\gwt-user-2.8.0-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\google\jsinterop\jsinterop-annotations\1.0.0-SNAPSHOT\jsinterop-annotations-1.0.0-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\google\jsinterop\jsinterop-annotations\1.0.0-SNAPSHOT\jsinterop-annotations-1.0.0-SNAPSHOT-sources.jar;C:\Users\retf\.m2\repository\javax\validation\validation-api\1.0.0.GA\validation-api-1.0.0.GA.jar;C:\Users\retf\.m2\repository\javax\validation\validation-api\1.0.0.GA\validation-api-1.0.0.GA-sources.jar;C:\Users\retf\.m2\repository\com\google\gwt\gwt-codeserver\2.8.0-SNAPSHOT\gwt-codeserver-2.8.0-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\google\gwt\gwt-dev\2.8.0-SNAPSHOT\gwt-dev-2.8.0-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\google\code\gson\gson\2.6.2\gson-2.6.2.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm\5.0.3\asm-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-util\5.0.3\asm-util-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-tree\5.0.3\asm-tree-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-commons\5.0.3\asm-commons-5.0.3.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\websocket\websocket-client\9.2.14.v20151106\websocket-client-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-util\9.2.14.v20151106\jetty-util-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-io\9.2.14.v20151106\jetty-io-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\websocket\websocket-common\9.2.14.v20151106\websocket-common-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\websocket\websocket-api\9.2.14.v20151106\websocket-api-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-webapp\9.2.14.v20151106\jetty-webapp-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-xml\9.2.14.v20151106\jetty-xml-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-servlet\9.2.14.v20151106\jetty-servlet-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-security\9.2.14.v20151106\jetty-security-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-servlets\9.2.14.v20151106\jetty-servlets-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-continuation\9.2.14.v20151106\jetty-continuation-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-http\9.2.14.v20151106\jetty-http-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-annotations\9.2.14.v20151106\jetty-annotations-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-plus\9.2.14.v20151106\jetty-plus-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-jndi\9.2.14.v20151106\jetty-jndi-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\javax\annotation\javax.annotation-api\1.2\javax.annotation-api-1.2.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\apache-jsp\9.2.14.v20151106\apache-jsp-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\jetty-server\9.2.14.v20151106\jetty-server-9.2.14.v20151106.jar;C:\Users\retf\.m2\repository\org\eclipse\jetty\toolchain\jetty-schemas\3.1.M0\jetty-schemas-3.1.M0.jar;C:\Users\retf\.m2\repository\javax\servlet\javax.servlet-api\3.1.0\javax.servlet-api-3.1.0.jar;C:\Users\retf\.m2\repository\org\mortbay\jasper\apache-jsp\8.0.9.M3\apache-jsp-8.0.9.M3.jar;C:\Users\retf\.m2\repository\org\mortbay\jasper\apache-el\8.0.9.M3\apache-el-8.0.9.M3.jar;C:\Users\retf\.m2\repository\com\vaadin\polymer\vaadin-gwt-polymer-elements\1.2.3.1-SNAPSHOT\vaadin-gwt-polymer-elements-1.2.3.1-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\googlecode\gwtquery\gwtquery\1.4.4-SNAPSHOT\gwtquery-1.4.4-SNAPSHOT.jar;C:\Users\retf\.m2\repository\com\google\gwt\gwt-user\2.7.0\gwt-user-2.7.0.jar;C:\Users\retf\.m2\repository\javax\validation\validation-api\1.0.0.GA\validation-api-1.0.0.GA.jar;C:\Users\retf\.m2\repository\javax\validation\validation-api\1.0.0.GA\validation-api-1.0.0.GA-sources.jar;C:\Users\retf\.m2\repository\com\google\gwt\gwt-dev\2.7.0\gwt-dev-2.7.0.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm\5.0.3\asm-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-util\5.0.3\asm-util-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-tree\5.0.3\asm-tree-5.0.3.jar;C:\Users\retf\.m2\repository\org\ow2\asm\asm-commons\5.0.3\asm-commons-5.0.3.jar com.google.gwt.dev.Compiler -logLevel INFO -style OBF -war E:\gwt-polymer-elements-master\demo\target\gwt-polymer-demo -localWorkers 4 -XnoclassMetadata -XnocheckCasts -XclosureCompiler -XfragmentCount -1 -sourceLevel 1.8 -optimize 9 -gen E:\gwt-polymer-elements-master\demo\target\.generated com.vaadin.polymer.demo.Demo
[ERROR] ]] failed with status 1
[ERROR] -> [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/MojoExecutionException

E:\gwt-polymer-elements-master\demo>[/s][/s][/b]

Hi Renato,

Check if enableClosureCompiler is active, if so, set it to false.