I'm trying to call a method on a java object that takes a single boolean argument - note boolean (native or primative) not Boolean (Object or Reference type).
Goes bang with...
Java::argx1: Method named method defined in class blah.blah.blah.Object was called with an incorrect number or type of arguments. The argument was True.
Various experiments with MakeJavaObject fail for the obvious reason they build True on the Mathematica side of JLink.