Here is a track and since java is availlable maybe someone can wrap the code and help me build a b4j library !
Utgard - pure Java OPC library
Utgard is an open source project offering an OPC library written in pure native Java, i.e. with no dependency on JNI or other DLLs. It is licensed under the GPL.
Support is currently provided for DA 2.0 client development, with server enumeration now implemented. DA 3.0 client and DA server side are planned to follow.
Utgard is a contributor to the larger
OpenSCADA project, and uses j-Interop (see below) for DCOM interoperability.