added collection.toSortedSet() for easier conversion to sorted setsand collection.notNull() so its easy to treat a nullable collection/list as a collection

stdlib/ktSrc/JavaCollections.kt

@@ -10,4 +10,8 @@ inline fun <T, R> java.util.Collection<T>.map(result: Collection<R> = ArrayList<
 }
 
 /** Returns true if the collection is not empty */
-inline fun <T> java.util.Collection<T>.notEmpty() : Boolean = !this.isEmpty()
+inline fun <T> java.util.Collection<T>.notEmpty() : Boolean = !this.isEmpty()
+
+/** Converts the nullable collection into an empty collection if its null */
+inline fun <T> java.util.Collection<T>?.notNull() : Collection<T>
+    = if (this != null) this else Collections.EMPTY_LIST as Collection<T>

stdlib/ktSrc/JavaIterables.kt

@@ -141,18 +141,24 @@ inline fun <T> java.lang.Iterable<T>.reverse() : List<T> {
   return answer
 }
 
+/* Copies the collection into the given collection */
 inline fun <T, C: Collection<T>> java.lang.Iterable<T>.to(result: C) : C {
   for (elem in this)
     result.add(elem)
   return result
 }
 
+/* Converts the collection into a LinkedList */
 inline fun <T> java.lang.Iterable<T>.toLinkedList() : LinkedList<T> = this.to(LinkedList<T>())
 
+/* Converts the collection into a List */
 inline fun <T> java.lang.Iterable<T>.toList() : List<T> = this.to(ArrayList<T>())
 
+/* Converts the collection into a Set */
 inline fun <T> java.lang.Iterable<T>.toSet() : Set<T> = this.to(HashSet<T>())
 
+/* Converts the collection into a SortedSet */
+inline fun <T> java.lang.Iterable<T>.toSortedSet() : SortedSet<T> = this.to(TreeSet<T>())
 /**
   TODO figure out necessary variance/generics ninja stuff... :)
 inline fun <in T> java.lang.Iterable<T>.toSortedList(transform: fun(T) : java.lang.Comparable<*>) : List<T> {

stdlib/ktSrc/JavaUtil.kt

@@ -54,6 +54,10 @@ inline fun <in T: java.lang.Comparable<T>> List<T>.sort(comparator: java.util.Co
   return this
 }
 
+/** Converts the nullable List into an empty List if its null */
+inline fun <T> java.util.List<T>?.notNull() : List<T>
+    = if (this != null) this else Collections.EMPTY_LIST as List<T>
+
 /**
   TODO figure out necessary variance/generics ninja stuff... :)
 inline fun <in T> List<T>.sort(transform: fun(T) : java.lang.Comparable<*>) : List<T> {