Thank you for the suggestions! I tried setting the system classloader with
-Djava.system.class.loader=org.codehaus.groovy.tools.RootLoader
and also tried
-Djava.system.class.loader=groovy.lang.GroovyClassloader
That indeed fixes the issue with "no suitable classloader available for
Grab" but unfortunately neither of them fixes the problem.
The issue is now that ant (called via AntBuilder) is unable to find the
h2 jdbc driver. It looks like RootLoader is a child first classloader so
it "should" have worked but I guess that ant's own classloader is not
playing well that setup.
The code is here in case anyone want to try it out:
https://github.com/perNyfelt/groovy-issues/tree/main/antbuilder
The error i am getting is as follows:
[0.003s][warning][cds] Archived non-system classes are disabled because
the java.system.class.loader property is specified (value =
"org.codehaus.groovy.tools.RootLoader"). To use archived non-system
classes, this property must not be set
Exception in thread "main" : Class Not Found: JDBC driver org.h2.Driver
could not be loaded
at
org.apache.tools.ant.taskdefs.JDBCTask.getDriver(JDBCTask.java:434)
at
org.apache.tools.ant.taskdefs.JDBCTask.getConnection(JDBCTask.java:365)
at
org.apache.tools.ant.taskdefs.SQLExec.getConnection(SQLExec.java:953)
at org.apache.tools.ant.taskdefs.SQLExec.execute(SQLExec.java:649)
at
org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:299)
at
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at
org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:99)
at groovy.ant.AntBuilder.performTask(AntBuilder.java:347)
at groovy.ant.AntBuilder.nodeCompleted(AntBuilder.java:286)
at
groovy.util.BuilderSupport.doInvokeMethod(BuilderSupport.java:161)
at groovy.ant.AntBuilder.doInvokeMethod(AntBuilder.java:219)
at groovy.util.BuilderSupport.invokeMethod(BuilderSupport.java:75)
at
org.codehaus.groovy.runtime.InvokerHelper.invokePogoMethod(InvokerHelper.java:651)
at
org.codehaus.groovy.runtime.InvokerHelper.invokeMethod(InvokerHelper.java:628)
at
org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeOnDelegationObjects(ClosureMetaClass.java:392)
at
org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:331)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1007)
at
org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321)
at sqltask$_run_closure1.doCall(sqltask.groovy:9)
at
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at
org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:343)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:328)
at
org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:280)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1007)
at groovy.lang.Closure.call(Closure.java:433)
at groovy.lang.Closure.call(Closure.java:422)
at
org.codehaus.groovy.runtime.DefaultGroovyMethods.with(DefaultGroovyMethods.java:368)
at
org.codehaus.groovy.runtime.DefaultGroovyMethods.with(DefaultGroovyMethods.java:313)
at org.codehaus.groovy.runtime.dgm$914.doMethodInvoke(Unknown
Source)
at
org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321)
at sqltask.run(sqltask.groovy:7)
at groovy.lang.GroovyShell.evaluate(GroovyShell.java:460)
at groovy.lang.GroovyShell.evaluate(GroovyShell.java:504)
at SqlTask.main(SqlTask.java:10)
I guess my best option is to mimic what the groovy command does exactly
and try to get that to work from java...
regards,
Per
*Jochen Theodorou* - Wednesday, July 9, 2025 5:46:19 PM GMT+2
If you run the program using the groovy command or a shell then there is
a GroovyClassLoader involved can be used instead of the systemloader.
Basically since Java9 Java does not use a url class loader as system
loader anymore. Which means we cannot support systemClassLoader=true in
case there is no rescuing GroovyClassLoader
you could try using -Djava.system.class.loader=... to set a class loader
using the fully qualified name. It should be a URLClassloader or child
of it and I guess the class needs to be on the classpath as well The
alternative is using a small program to load the classpath and start the
program. In Groovy we are using RootLoader for this. Or you use
GroovyStarter bye Jochen
On 7/8/25 12:51, Per Nyfelt wrote:
Hi,
I am trying to figure out a way to
use @GrabConfig(systemClassLoader=true) in a ScritpEngine (or
GroovyShell, does not matter.
The following script works without any problem using the groovy
command (.e.g `groovy sqltaskExample.groovy`):
@GrabConfig(systemClassLoader=true)
@Grab('com.h2database:h2:2.3.232')
import groovy.ant.AntBuilder
println"Groovy ClassLoader: ${this.class.classLoader}" def project =new
AntBuilder()
project.with { sql(
driver:"org.h2.Driver",
url:"jdbc:h2:mem:AZ",
userid:"sa",
password:"",
// direct printed output into a text file: output:"query.out",
print:"yes",// enable printing of result sets showheaders:"false",// suppress column names showtrailers:"false"
// suppress "N rows returned" line ){ transaction(""" CREATE TABLE some_table ( id INT, name VARCHAR(200) );
""")
transaction(""" INSERT INTO some_table (id, name) VALUES (1, 'hello'); """)
transaction(""" SELECT name FROM some_table WHERE id = 1; """)
} // now the file query.out contains exactly "hello"
loadfile(property:"row1col1",srcFile:"query.out")
echo(message:'row1col1 = ${row1col1}')
delete(file:"query.out")
}
Calling that from java however does not work:, e.g.
public class ShellWithGrabSupport {
public static void main(String[] args)throws Exception {
GroovyScriptEngine gse =new GroovyScriptEngine(".");
gse.run("sqltaskExample.groovy",new Binding());
}
}
Results in "No Suitable classloader found for Grab"
I have tried stuff like this:
System.setProperty("groovy.grape.enable","true");
System.setProperty("groovy.grape.report.downloads","true");
GroovyClassLoader gcl =new
GroovyClassLoader(ClassLoader.getSystemClassLoader());
CompilerConfiguration config =new CompilerConfiguration();
config.setRecompileGroovySource(true);
GroovyShell shell =new GroovyShell(gcl, config);
Script s = shell.parse(new File("sqltaskExample.groovy"));
s.run();
and
System.setProperty("groovy.grape.report.downloads","true");
System.setProperty("groovy.grape.enable","true");
// Ensure system classloader is used
Thread.currentThread().setContextClassLoader(ClassLoader.getSystemClassLoader());
// This mimics what the `groovy` CLI does GroovyMain.main(new
String[]{"sqltaskExample.groovy"});
All with the same result.
I use the following to bootstrap java:
gl="$GROOVY_HOME/lib" v="4.0.27"
cp="$gl/groovy-$v.jar:$gl/groovy-ant-$v.jar:$gl/groovy-ant-$v.jar:$gl/ant-1.10.15.jar:\
$gl/ant-launcher-1.10.15.jar:$gl/ivy-2.5.3.jar" java -cp"$cp" ShellWithGrabSupport.java
So since ant is loaded by the system classloader, I must
use @GrabConfig(systemClassLoader=true) in the groovy script for the
jdbc driver, otherwise the sql ant task will not be able to find it.
This minimum, reproducible example is here:
https://github.com/perNyfelt/groovy-issues/tree/main/grabconfig
The details of the error are as follows:
Exception in thread "main"
org.codehaus.groovy.control.MultipleCompilationErrorsException:
startup failed:
General error during conversion: No suitable ClassLoader found for grab
java.lang.RuntimeException: No suitable ClassLoader found for grab
at groovy.grape.GrapeIvy.chooseClassLoader(GrapeIvy.groovy:179)
at groovy.grape.GrapeIvy.grab(GrapeIvy.groovy:273)
at groovy.grape.Grape$1.run(Grape.java:172)
at groovy.grape.Grape$1.run(Grape.java:158)
at
java.base/java.security.AccessController.doPrivileged(AccessController.java:319)
at groovy.grape.Grape.grab(Grape.java:158)
at
groovy.grape.GrabAnnotationTransformation.visit(GrabAnnotationTransformation.java:380)
at
org.codehaus.groovy.transform.ASTTransformationVisitor.lambda$addPhaseOperationsForGlobalTransforms$5(ASTTransformationVisitor.java:374)
at
org.codehaus.groovy.control.CompilationUnit$ISourceUnitOperation.doPhaseOperation(CompilationUnit.java:906)
at
org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:701)
at
org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:675)
at
groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:365)
at
groovy.lang.GroovyClassLoader.lambda$parseClass$2(GroovyClassLoader.java:314)
at
org.codehaus.groovy.runtime.memoize.StampedCommonCache.compute(StampedCommonCache.java:163)
at
org.codehaus.groovy.runtime.memoize.StampedCommonCache.getAndPut(StampedCommonCache.java:154)
at
groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:314)
at
groovy.util.GroovyScriptEngine$ScriptClassLoader.doParseClass(GroovyScriptEngine.java:231)
at
groovy.util.GroovyScriptEngine$ScriptClassLoader.parseClass(GroovyScriptEngine.java:218)
at
groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:298)
at
groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:263)
at
groovy.util.GroovyScriptEngine.loadScriptByName(GroovyScriptEngine.java:534)
at
groovy.util.GroovyScriptEngine.createScript(GroovyScriptEngine.java:584)
at groovy.util.GroovyScriptEngine.run(GroovyScriptEngine.java:571)
at ShellWithGrabSupport.main(ShellWithGrabSupport.java:7)
at
...
Does anyone know a way?
