I have OSB Project that I need to export as Java client Jar.
I think, there is an option in Eclipse(OEPE) to export your OSB project to Java client Jar. It converts your proxy/business/xml/wsdl to java classes.
Assuming your requirement is to invoke OSB proxy service from your Java code and you require webservice client to do that, you can use the below command from your command prompt to generate the Java client from the wsdl.
wsimport -d %PATH_FOR_JAVA_CLIENT% %WSDL_FILE_LOCATION% -keep -Xnocompile -verbose
wsimport -d D:\TestProject\src D:\OSBProxyService.wsdl -keep -Xnocompile -verbose