Please use the following links to download the specification.
OSGi Service Platform Release 4 Version 4.1 Core Specification
OSGi Service Platform Release 4 Version 4.1 Compendium Specification
OSGi Service Platform Release 4 Version 4.1 Core Companion Code
OSGi Service Platform Release 4 Version 4.1 Compendium Companion Code
OSGi Service Platform Release 4 Version 4.1 Minimum Execution Environment
OSGi Service Platform Release 4 Version 4.1 Foundation Execution Environment