Not sure if the title is correct but ...

Trying to rewrite OGNL-9 i add in the .java
    @Message("page-title")
    public abstract String getTitle(int partnersCount);

and use any of the expressions
   ognl:getTitle(partners.size)
   ognl:getTitle(partners.size())
   ognl:getTitle(getPartners().size())
   ognl:getTitle(getPartners().size)

BTW, the .java contains a getPartners() method that returns a collection

In the first case I get
Error compiling expression on object $OurPartners_47@3c1[OurPartners] with expression node getTitle(partners.size) getter body: null setter body: nulljava.lang.ArrayIndexOutOfBoundsException: 0
and in the others
Error compiling expression on object $NonflowBorder_156@ea72b4a1[OurPartners/Border] with expression node title getter body: null setter body: nulltitle

They all produce the same stacktrace:

org.apache.tapestry.services.impl.HiveMindExpressionCompiler.compileExpression(HiveMindExpressionCompiler.java:258)
ognl.OgnlRuntime.compileExpression(OgnlRuntime.java:384)
ognl.Ognl.compileExpression(Ognl.java:123)
org.apache.tapestry.services.impl.ExpressionCacheImpl.parse(ExpressionCacheImpl.java:129)
org.apache.tapestry.services.impl.ExpressionCacheImpl.getCompiledExpression(ExpressionCacheImpl.java:91)
$ExpressionCache_1112ff335b1.getCompiledExpression($ExpressionCache_1112ff335b1.java)
org.apache.tapestry.binding.ExpressionBinding.resolveExpression(ExpressionBinding.java:121)
org.apache.tapestry.binding.ExpressionBinding.getObject(ExpressionBinding.java:112)
org.apache.tapestry.binding.AbstractBinding.getObject(AbstractBinding.java:84)
$Border_22.getTitle($NonflowBorder_22.java)
ognl.ASTProperty4142218Accessor.get(ASTProperty4142218Accessor.java)
org.apache.tapestry.services.impl.ExpressionEvaluatorImpl.read(ExpressionEvaluatorImpl.java:131)
$ExpressionEvaluator_1112ff335af.read($ExpressionEvaluator_1112ff335af.java)
org.apache.tapestry.binding.ExpressionBinding.resolveExpression(ExpressionBinding.java:127)
org.apache.tapestry.binding.ExpressionBinding.getObject(ExpressionBinding.java:112)
org.apache.tapestry.binding.AbstractBinding.getObject(AbstractBinding.java:84)
$Insert_6.getValue($Insert_6.java)
org.apache.tapestry.components.Insert.renderComponent(Insert.java:48)
org.apache.tapestry.AbstractComponent.render(AbstractComponent.java:708)
org.apache.tapestry.services.impl.DefaultResponseBuilder.render(DefaultResponseBuilder.java:184)
org.apache.tapestry.AbstractComponent.renderBody(AbstractComponent.java:521)
org.apache.tapestry.html.Body.renderComponent(Body.java:38)
org.apache.tapestry.AbstractComponent.render(AbstractComponent.java:708)