java.util.Collection

is imported to:

.   bluej.collect
.   bluej.editor
.   bluej.editor.moe
.   bluej.editor.stride
.   bluej.extensions
.   bluej.graph
.   bluej.groupwork.git
.   bluej.parser
.   bluej.pkgmgr
.   bluej.pkgmgr.target
.   bluej.stride.framedjava.ast
.   bluej.stride.generic
.   bluej.utility
.   greenfoot
.   greenfoot.collision
.   greenfoot.core
.   greenfoot.mouse
.   threadchecker