General error during conversion: No suitable ClassLoader found for grab

Question

I've try code below...

@Grapes([
    @Grab('org.hsqldb:hsqldb:2.0.0'),
    @GrabConfig(systemClassLoader=true, initContextClassLoader=true)
])
import groovy.sql.Sql
println Class.forName('org.hsqldb.jdbc.JDBCDriver').newInstance()

It works in groovyConsole, but failed to run with Web Start. Following are error messages.

startup failed:
General error during conversion: No suitable ClassLoader found for grab

java.lang.RuntimeException: No suitable ClassLoader found for grab
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.codehaus.groovy.reflection.CachedConstructor.invoke(CachedConstructor.java:77)
    at org.codehaus.groovy.runtime.callsite.ConstructorSite$ConstructorSiteNoUnwrapNoCoerce.callConstructor(ConstructorSite.java:102)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:54)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:182)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:190)
    at groovy.grape.GrapeIvy.chooseClassLoader(GrapeIvy.groovy:173)
    at groovy.grape.GrapeIvy$chooseClassLoader.callCurrent(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:46)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:133)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:141)
    at groovy.grape.GrapeIvy.grab(GrapeIvy.groovy:239)
    at groovy.grape.Grape.grab(Grape.java:141)
    at groovy.grape.GrabAnnotationTransformation.visit(GrabAnnotationTransformation.java:282)
    at org.codehaus.groovy.transform.ASTTransformationVisitor$3.call(ASTTransformationVisitor.java:302)
    at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:839)
    at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:544)
    at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:520)
    at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:497)
    at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:306)
    at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:287)
    at groovy.lang.GroovyShell.parseClass(GroovyShell.java:731)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:743)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:698)
    at groovy.lang.GroovyShell.evaluate(GroovyShell.java:648)
    at groovy.lang.GroovyShell.evaluate(GroovyShell.java:636)
    at com.lyhdev.mrcode.ScriptLoader.loadGroovy(Unknown Source)
    at com.lyhdev.mrcode.ScriptLoader$loadGroovy.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
    at Script1.run(Script1.groovy:30)
    at groovy.lang.GroovyShell.evaluate(GroovyShell.java:650)
    at groovy.lang.GroovyShell.evaluate(GroovyShell.java:636)
    at com.lyhdev.mrcode.ScriptLoader.loadGroovy(Unknown Source)
    at com.lyhdev.mrcode.ScriptLoader.main(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.sun.javaws.Launcher.executeApplication(Launcher.java:1804)
    at com.sun.javaws.Launcher.executeMainClass(Launcher.java:1750)
    at com.sun.javaws.Launcher.doLaunchApp(Launcher.java:1512)
    at com.sun.javaws.Launcher.run(Launcher.java:130)
    at java.lang.Thread.run(Thread.java:662)

1 error 

Answer 1

Dunno whether it might help, but see http://www.randomactsofsentience.com/2012/01/that-darned-no-suitable-classloader.html if this helps.

Answer 2

It's all about what classloaders are involved. For example I see the same problem with running groovy from ant. I seems because the system classloader when you run groovy under ant or web start is not a groovy class loader or a root loader. See isValidTargetClassLoader() from GrapeIvy.groovy.

One solution to the problem would be to make sure you have a groovy RootLoader, add all necessary classpath to it in your script and then run your app from your groovy script/class. Would be tricky with web start I guess.