Question

I am using ant to compile gwt but it takes long long time to compile. near 50sec.

How can I speed up compiling process.

ant task is

<target name="gwtc" description="GWT compile to JavaScript">
    <java failonerror="true" fork="true" classname="com.google.gwt.dev.Compiler">
        <classpath>
            <pathelement location="${src.dir}"/>
            <path refid="compile.classpath"/>
        </classpath>
        <jvmarg value="-Xmx256M"/>
        <!--<arg value="-style"/>-->
        <!--<arg value="DETAILED"/>-->
        <arg value="com.typingApplication.TypingApplication"/>
        <arg value="-war" />
        <arg value="${build.dir}" />
    </java>
</target>

Answer 1

Add the param -localWorkers. This specifies that the permutations are done in parallel. Especially on a multicore machine this makes sense. The parameter for the argument is the number of parallel runs. I tested several combinations and found that 4 gave the best results(fastest, even while i tested it on a 6 core/12GB machine). So just try out what works best in your situation, also experiment with the memory value. for example try 512 instead of 256.

 <arg value="-localWorkers" />
 <arg value="4" />

A second option is -draftCompile. This skips some compile optimizations, so it’s not an option you want to use for the production release. But in development it saves compilation time.

Or buy a faster machine;-) processor speed matters in this case