question: protected Package definePackage ( String packageName , Manifest manifest , URL url ) throws IllegalArgumentException { Attributes mainAttributes = manifest . getMainAttributes ( ) ; String dirName = packageName . replace ( '.' , '/' ) + "/" ; Attributes packageAttributes = manifest . getAttributes ( dirName ) ; boolean noEntry = false ; if ( packageAttributes == null ) { noEntry = true ; packageAttributes = mainAttributes ; } String specificationTitle = packageAttributes . getValue ( Attributes . Name . SPECIFICATION_TITLE ) ; if ( specificationTitle == null && ! noEntry ) { specificationTitle = mainAttributes . getValue ( Attributes . Name . SPECIFICATION_TITLE ) ; } String specificationVersion = packageAttributes . getValue ( Attributes . Name . SPECIFICATION_VERSION ) ; if ( specificationVersion == null && ! noEntry ) { specificationVersion = mainAttributes . getValue ( Attributes . Name . SPECIFICATION_VERSION ) ; } String specificationVendor = packageAttributes . getValue ( Attributes . Name . SPECIFICATION_VENDOR ) ; if ( specificationVendor == null && ! noEntry ) { specificationVendor = mainAttributes . getValue ( Attributes . Name . SPECIFICATION_VENDOR ) ; } String implementationTitle = packageAttributes . getValue ( Attributes . Name . IMPLEMENTATION_TITLE ) ; if ( implementationTitle == null && ! noEntry ) { implementationTitle = mainAttributes . getValue ( Attributes . Name . IMPLEMENTATION_TITLE ) ; } String implementationVersion = packageAttributes . getValue ( Attributes . Name . IMPLEMENTATION_VERSION ) ; if ( implementationVersion == null && ! noEntry ) { implementationVersion = mainAttributes . getValue ( Attributes . Name . IMPLEMENTATION_VERSION ) ; } String implementationVendor = packageAttributes . getValue ( Attributes . Name . IMPLEMENTATION_VENDOR ) ; if ( implementationVendor == null && ! noEntry ) { implementationVendor = mainAttributes . getValue ( Attributes . Name . IMPLEMENTATION_VENDOR ) ; } return definePackage ( packageName , specificationTitle , specificationVersion , specificationVendor , implementationTitle , implementationVersion , implementationVendor , isSealed ( manifest , dirName ) ? url : null ) ; }
target:  Defines a new package using the information extracted from the specified manifest.