question: private boolean isProjectUsingDefaultSdk ( T projectSdk ) { if ( ! isDefaultSdk ( projectSdk ) ) { return false ; } try { IClasspathEntry entry = ClasspathUtilities . findClasspathEntryContainer ( javaProject . getRawClasspath ( ) , doGetContainerId ( ) ) ; if ( entry != null ) { if ( SdkClasspathContainer . isDefaultContainerPath ( doGetContainerId ( ) , entry . getPath ( ) ) ) { return true ; } } } catch ( CoreException ce ) { CorePluginLog . logError ( ce ) ; } return false ; }
target:  Returns true if the given project SDK is actually the default SDK for the workspace AND the project has a classpath container entry for the given SDK that indicates that the workspace default should actually be used (i.e. no trailing segments). Also returns true if the project SDK is the default SDK for the workspace and the project does not have a classpath container entry for the SDK.