Sunday, July 28, 2019

JSNI method compilation error with javascript regular expression

Hello everyone,

To simplify the description of the problem, I use an official example to illustrate the problem。

  1. Follow the GWT Getting Started to create a GWT project 

    webAppCreator -out MyWebApp com.mycompany.mywebapp.MyWebApp

  2. Define a JSNI method with java regular expression and call it  in the EntryPoint class com.mycompany.mywebapp.client.MyWebApp

        public static native void methodWithRegularExpression()/*-{
            var reg = /^[\\w+/_-]+[=]{0,2}$/
            console.log("reg:" + reg)

         * This is the entry point method.
        public void onModuleLoad() {

  3. Compile the project with the following Ant task(gwtc)

       <!-- Arguments to gwtc and devmode targets -->
      <property name="gwt.args" value="" />

      <!-- Configure path to GWT SDK -->
      <property name="gwt.sdk" location="G:/Google/gwt-2.8.2" />

      <path id="project.class.path">
        <fileset dir="lib" includes="**/*.jar"/>
        <pathelement location="war/WEB-INF/classes"/>
        <pathelement location="${gwt.sdk}/gwt-user.jar"/>
        <pathelement location="${gwt.sdk}/gwt-dev.jar"/>
        <pathelement location="${gwt.sdk}/validation-api-1.0.0.GA.jar"/>
        <pathelement location="${gwt.sdk}/validation-api-1.0.0.GA-sources.jar"/>
        <fileset dir="war/WEB-INF/lib" includes="**/*.jar"/>
        <!-- Add any additional non-server libs (such as JUnit) here -->

      <target name="libs" description="Copy libs to WEB-INF/lib">
        <mkdir dir="war/WEB-INF/lib" />
        <copy todir="war/WEB-INF/lib" file="${gwt.sdk}/gwt-servlet.jar" />
        <copy todir="war/WEB-INF/lib" file="${gwt.sdk}/gwt-servlet-deps.jar" />
        <!-- Add any additional server libs that need to be copied -->

      <target name="javac" depends="libs" description="Compile java source to bytecode">
        <mkdir dir="war/WEB-INF/classes"/>
        <javac srcdir="src" includes="**" encoding="utf-8"
            source="1.7" target="1.7" nowarn="true"
            debug="true" debuglevel="lines,vars,source">
          <classpath refid="project.class.path"/>
        <copy todir="war/WEB-INF/classes">
          <fileset dir="src" excludes="**/*.java"/>

      <target name="gwtc" depends="javac" description="GWT compile to JavaScript (production mode)">
        <java failonerror="true" fork="true" classname="" maxmemory="512m">
            <pathelement location="src"/>
            <path refid="project.class.path"/>
          <arg line="-war"/>
          <arg value="war"/>
          <!-- Additional arguments like -style PRETTY or -logLevel DEBUG -->
          <arg line="${gwt.args}"/>
          <arg line="-strict"/>
          <arg value="com.mycompany.mywebapp.MyWebApp"/>

  4. Build failed

        [javac] G:\Google\MyWebApp\build.xml:34: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
        [javac] Compiling 1 source file to G:\Google\MyWebApp\war\WEB-INF\classes

         [java] 七月 29, 2019 10:31:07 上午 java.util.prefs.WindowsPreferences <init>
         [java] 警告: Could not open/create prefs root node Software\JavaSoft\Prefs at root 0x80000002. Windows RegCreateKeyEx(...) returned error code 5.
         [java] Compiling module com.mycompany.mywebapp.MyWebApp
         [java]    Tracing compile failure path for type 'com.mycompany.mywebapp.client.MyWebApp'
         [java]       [ERROR] Errors in 'file:/G:/Google/MyWebApp/src/com/mycompany/mywebapp/client/'
         [java]          [ERROR] Line 44: missing ; before statement
         [java] >         var reg = /^[\\w+/_-]+[=]{0,2}$/
         [java] > ---------------------------^
         [java]    Finding entry point classes
         [java]       Tracing compile failure path for type 'com.mycompany.mywebapp.client.MyWebApp'
         [java]          [ERROR] Errors in 'file:/G:/Google/MyWebApp/src/com/mycompany/mywebapp/client/'
         [java]             [ERROR] Line 44: missing ; before statement
         [java] >         var reg = /^[\\w+/_-]+[=]{0,2}$/
         [java] > ---------------------------^
         [java]       [ERROR] Hint: Check the inheritance chain from your module; it may not be inheriting a required module or a module may not be adding its source path entries properly


More information:

ant version:
Apache Ant(TM) version 1.9.14 compiled on March 12 2019

GWT SDK version:

In the end, does anyone know how to solve this problem? 

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