Replaced == null()eq null(ne null)

31 files changed, 83 insertions, 83 deletions

diff --git a/src/library/scala/Application.scala b/src/library/scala/Application.scala
index 9b268abeae..672969e91c 100644
--- a/src/library/scala/Application.scala
+++ b/src/library/scala/Application.scala
@@ -50,7 +50,7 @@ trait Application {
    *  @param args the arguments passed to the main method
    */
   def main(args: Array[String]) = {
-    if (getProperty("scala.time") != null) {
+    if (getProperty("scala.time") ne null) {
       val total = currentTime - executionStart
       Console.println("[total " + total + "ms]")
     }
diff --git a/src/library/scala/BigInt.scala b/src/library/scala/BigInt.scala
index 8efad433b1..9be8a45dbd 100644
--- a/src/library/scala/BigInt.scala
+++ b/src/library/scala/BigInt.scala
@@ -32,7 +32,7 @@ object BigInt {
   def apply(i: Int): BigInt =
     if (minCached <= i && i <= maxCached) {
       var n = cache(i)
-      if (n == null) { n = new BigInt(BigInteger.valueOf(i)); cache(i) = n }
+      if (n eq null) { n = new BigInt(BigInteger.valueOf(i)); cache(i) = n }
       n
     } else new BigInt(BigInteger.valueOf(i))
 
diff --git a/src/library/scala/Console.scala b/src/library/scala/Console.scala
index 8fa4285ab6..7cc8e9d4e9 100644
--- a/src/library/scala/Console.scala
+++ b/src/library/scala/Console.scala
@@ -142,7 +142,7 @@ object Console {
    *  @param obj the object to print.
    */
   def print(obj: Any): Unit =
-    out.print(if (obj == null) "null" else obj.toString())
+    out.print(if (null == obj) "null" else obj.toString())
 
   /** Flush the output stream. This function is required when partial
    *  output (i.e. output not terminated by a new line character) has
@@ -173,7 +173,7 @@ object Console {
   // todo: Uncurry
   def printf(text: String)(args: Any*): Unit =
     out.print(
-      if (text == null) "null"
+      if (text eq null) "null"
       else MessageFormat.format(text, textParams(args))
     )
 
diff --git a/src/library/scala/Enumeration.scala b/src/library/scala/Enumeration.scala
index b92ad6ca4e..cff1c41238 100644
--- a/src/library/scala/Enumeration.scala
+++ b/src/library/scala/Enumeration.scala
@@ -66,7 +66,7 @@ abstract class Enumeration(initial: Int, names: String*) {
   private var vcache: List[Value] = null
 
   private def updateCache: List[Value] =
-    if (vcache == null) {
+    if (vcache eq null) {
       vcache = values.values.toList.sort((p1, p2) => p1.id < p2.id);
       vcache
     } else
@@ -132,7 +132,7 @@ abstract class Enumeration(initial: Int, names: String*) {
       topId = nextId
     def id = i
     override def toString() =
-      if (name == null) Enumeration.this.name + "(" + i + ")"
+      if (name eq null) Enumeration.this.name + "(" + i + ")"
       else name
   }
 }
diff --git a/src/library/scala/MatchError.scala b/src/library/scala/MatchError.scala
index 6ef969b97c..57ada9efbd 100644
--- a/src/library/scala/MatchError.scala
+++ b/src/library/scala/MatchError.scala
@@ -24,7 +24,7 @@ import Predef._
 object MatchError {
 
   def string(obj: Any) =
-    if(obj != null) obj.toString() else "null"
+    if (null != obj) obj.toString() else "null"
 
   // todo: change pattern matcher so that dummy type parameter T can be removed.
   def fail[T](source: String, line: Int): Nothing =
diff --git a/src/library/scala/collection/mutable/DoubleLinkedList.scala b/src/library/scala/collection/mutable/DoubleLinkedList.scala
index f2916d39e9..5ed7a5dbb8 100644
--- a/src/library/scala/collection/mutable/DoubleLinkedList.scala
+++ b/src/library/scala/collection/mutable/DoubleLinkedList.scala
@@ -28,24 +28,24 @@ abstract class DoubleLinkedList[A, This >: Null <: DoubleLinkedList[A, This]]
   var prev: This
 
   override def append(that: This): Unit =
-    if (that == null)
+    if (that eq null)
       ()
-    else if (next == null) {
+    else if (next eq null) {
       next = that
       that.prev = this
     } else
       next.append(that)
 
-  override def insert(that: This): Unit = if (that != null) {
+  override def insert(that: This): Unit = if (that ne null) {
     that.append(next)
     next = that
     that.prev = this
   }
 
   def remove: Unit = {
-    if (next != null)
+    if (next ne null)
       next.prev = prev
-    if (prev != null)
+    if (prev ne null)
       prev.next = next
     prev = null
     next = null
diff --git a/src/library/scala/collection/mutable/ListBuffer.scala b/src/library/scala/collection/mutable/ListBuffer.scala
index 5ec6e6eb7c..1c248835e9 100644
--- a/src/library/scala/collection/mutable/ListBuffer.scala
+++ b/src/library/scala/collection/mutable/ListBuffer.scala
@@ -248,7 +248,7 @@ final class ListBuffer[A] extends Buffer[A] {
       if (!hasNext) {
         throw new NoSuchElementException("next on empty Iterator")
       } else {
-        if (cursor == null) cursor = start else cursor = cursor.tail
+        if (cursor eq null) cursor = start else cursor = cursor.tail
         cursor.head
       }
   }
diff --git a/src/library/scala/collection/mutable/MutableList.scala b/src/library/scala/collection/mutable/MutableList.scala
index 6e57074641..8983949aaa 100644
--- a/src/library/scala/collection/mutable/MutableList.scala
+++ b/src/library/scala/collection/mutable/MutableList.scala
@@ -69,12 +69,12 @@ trait MutableList[A] extends Seq[A] with PartialFunction[Int, A] {
   /** Returns an iterator over all elements of this list.
    */
   def elements: Iterator[A] =
-    if (first == null) Nil.elements else first.elements
+    if (first eq null) Nil.elements else first.elements
 
   /** Returns an instance of <code>scala.List</code> containing the same
    *  sequence of elements.
    */
-  override def toList: List[A] = if (first == null) Nil else first.toList
+  override def toList: List[A] = if (first eq null) Nil else first.toList
 
   override protected def stringPrefix: String = "MutableList"
 }
diff --git a/src/library/scala/collection/mutable/Queue.scala b/src/library/scala/collection/mutable/Queue.scala
index 7d31b2b66e..271c8d680d 100644
--- a/src/library/scala/collection/mutable/Queue.scala
+++ b/src/library/scala/collection/mutable/Queue.scala
@@ -27,7 +27,7 @@ class Queue[A] extends MutableList[A] {
    *
    *  @return true, iff there is no element in the queue.
    */
-  override def isEmpty: Boolean = (first == null)
+  override def isEmpty: Boolean = (first eq null)
 
   /** Inserts a single element at the end of the queue.
    *
@@ -64,12 +64,12 @@ class Queue[A] extends MutableList[A] {
    *  @return the first element of the queue.
    */
   def dequeue: A =
-    if (first == null)
+    if (first eq null)
       throw new NoSuchElementException("queue empty")
     else {
       val res = first.elem
       first = first.next
-      if (first == null) last = null
+      if (first eq null) last = null
       len = len - 1
       res
     }
@@ -81,15 +81,15 @@ class Queue[A] extends MutableList[A] {
    *  @return the first element of the queue for which p yields true
    */
   def dequeueFirst(p: A => Boolean): Option[A] =
-    if (first == null)
+    if (first eq null)
       None
     else if (p(first.elem)) {
       val res: Option[A] = Some(first.elem)
       first = first.next
       len = len - 1
-      if (first == null) {
+      if (first eq null) {
         last = null
-      } else if (first.next == null) {
+      } else if (first.next eq null) {
         last = first
       }
       res
@@ -108,16 +108,16 @@ class Queue[A] extends MutableList[A] {
    */
   def dequeueAll(p: A => Boolean): Seq[A] = {
     val res = new ArrayBuffer[A]
-    if (first == null)
+    if (first eq null)
       res
     else {
       while (p(first.elem)) {
         res += first.elem
         first = first.next
         len = len - 1
-        if (first == null) {
+        if (first eq null) {
           last = null
-        } else if (first.next == null) {
+        } else if (first.next eq null) {
           last = first
         }
       }
@@ -132,15 +132,15 @@ class Queue[A] extends MutableList[A] {
 
   private def extractFirst(start: LinkedList[A], p: A => Boolean): Option[LinkedList[A]] = {
     var cell = start
-    while ((cell.next != null) && !p(cell.next.elem)) {
+    while ((cell.next ne null) && !p(cell.next.elem)) {
       cell = cell.next
     }
-    if (cell.next == null)
+    if (cell.next eq null)
       None
     else {
       val res: Option[LinkedList[A]] = Some(cell.next)
       cell.next = cell.next.next
-      if (cell.next == null)
+      if (cell.next eq null)
         last = cell
       len = len - 1
       res
diff --git a/src/library/scala/collection/mutable/SingleLinkedList.scala b/src/library/scala/collection/mutable/SingleLinkedList.scala
index 6a889fc49e..2fc51ad9a2 100644
--- a/src/library/scala/collection/mutable/SingleLinkedList.scala
+++ b/src/library/scala/collection/mutable/SingleLinkedList.scala
@@ -28,29 +28,29 @@ abstract class SingleLinkedList[A, This >: Null <: SingleLinkedList[A, This]]
 
   var next: This
 
-  def length: Int = 1 + (if (next == null) 0 else next.length)
+  def length: Int = 1 + (if (next eq null) 0 else next.length)
 
   def append(that: This): Unit =
-    if (next == null) next = that else next.append(that)
+    if (next eq null) next = that else next.append(that)
 
-  def insert(that: This): Unit = if (that != null) {
+  def insert(that: This): Unit = if (that ne null) {
     that.append(next)
     next = that
   }
 
   def apply(n: Int): A =
     if (n == 0) elem
-    else if (next == null) throw new IndexOutOfBoundsException("unknown element")
+    else if (next eq null) throw new IndexOutOfBoundsException("unknown element")
     else next.apply(n - 1)
 
   def get(n: Int): Option[A] =
     if (n == 0) Some(elem)
-    else if (next == null) None
+    else if (next eq null) None
     else next.get(n - 1)
 
   def elements: Iterator[A] = new Iterator[A] {
     var elems = SingleLinkedList.this
-    def hasNext = (elems != null)
+    def hasNext = (elems ne null)
     def next = {
       val res = elems.elem
       elems = elems.next
diff --git a/src/library/scala/collection/mutable/Stack.scala b/src/library/scala/collection/mutable/Stack.scala
index 825e87c629..e3aa316c21 100644
--- a/src/library/scala/collection/mutable/Stack.scala
+++ b/src/library/scala/collection/mutable/Stack.scala
@@ -25,7 +25,7 @@ class Stack[A] extends MutableList[A] {
    *
    *  @return true, iff there is no element on the stack
    */
-  override def isEmpty: Boolean = (first == null)
+  override def isEmpty: Boolean = (first eq null)
 
   /** Pushes a single element on top of the stack.
    *
@@ -63,7 +63,7 @@ class Stack[A] extends MutableList[A] {
    *  @throws Predef.NoSuchElementException
    *  @return the top element
    */
-  def top: A = if (first == null) throw new NoSuchElementException("stack empty") else first.elem
+  def top: A = if (first eq null) throw new NoSuchElementException("stack empty") else first.elem
 
   /** Removes the top element from the stack.
    *
@@ -71,7 +71,7 @@ class Stack[A] extends MutableList[A] {
    *  @return the top element
    */
   def pop: A =
-    if (first != null) {
+    if (first ne null) {
       val res = first.elem
       first = first.next
       len = len - 1;
diff --git a/src/library/scala/concurrent/Actor.scala b/src/library/scala/concurrent/Actor.scala
index 8f2534bb95..15b77bf3fd 100644
--- a/src/library/scala/concurrent/Actor.scala
+++ b/src/library/scala/concurrent/Actor.scala
@@ -37,7 +37,7 @@ abstract class Actor extends Thread {
   private var pid: Pid = null
 
   def self = {
-    if (pid == null) pid = new Pid(this)
+    if (pid eq null) pid = new Pid(this)
     pid
   }
 
diff --git a/src/library/scala/concurrent/Channel.scala b/src/library/scala/concurrent/Channel.scala
index f7a156271f..bab6345ab9 100644
--- a/src/library/scala/concurrent/Channel.scala
+++ b/src/library/scala/concurrent/Channel.scala
@@ -36,7 +36,7 @@ class Channel[a] {
   }
 
   def read: a = synchronized {
-    if (written.next == null) {
+    if (null == written.next) {
       nreaders = nreaders + 1; wait(); nreaders = nreaders - 1
     }
     val x = written.elem
diff --git a/src/library/scala/concurrent/MailBox.scala b/src/library/scala/concurrent/MailBox.scala
index 7a8b4eac20..e1399e9e58 100644
--- a/src/library/scala/concurrent/MailBox.scala
+++ b/src/library/scala/concurrent/MailBox.scala
@@ -31,13 +31,13 @@ class MailBox extends AnyRef with ListQueueCreator {
     def isDefinedAt(msg: Message) = receiver.isDefinedAt(msg)
 
     def receive(): a = synchronized {
-      while (msg == null) wait()
+      while (msg eq null) wait()
       receiver(msg)
     }
 
     def receiveWithin(msec: long): a = synchronized {
-      if (msg == null) wait(msec)
-      receiver(if (msg != null) msg else TIMEOUT)
+      if (msg eq null) wait(msec)
+      receiver(if (msg ne null) msg else TIMEOUT)
     }
   }
 
@@ -157,13 +157,13 @@ trait LinkedListQueueCreator {
     def extractFirst(l: t, p: a => boolean): Option[Pair[a, t]] = {
       var xs = l._1
       var xs1 = xs.next
-      while (xs1 != null && !p(xs1.elem)) {
+      while ((xs1 ne null) && !p(xs1.elem)) {
         xs = xs1
         xs1 = xs1.next
       }
-      if (xs1 != null) {
+      if (xs1 ne null) {
         xs.next = xs1.next
-        if (xs.next == null)
+        if (xs.next eq null)
           Some(Pair(xs1.elem, Pair(l._1, xs)))
         else
           Some(Pair(xs1.elem, l))
diff --git a/src/library/scala/mobile/Code.scala b/src/library/scala/mobile/Code.scala
index e7166bfc1a..33ddc8f6fa 100644
--- a/src/library/scala/mobile/Code.scala
+++ b/src/library/scala/mobile/Code.scala
@@ -185,7 +185,7 @@ class Code(clazz: java.lang.Class) {
       val method = clazz.getMethod(methName, argTypes)
       var obj: JObject = null
       if (! Modifier.isStatic(method.getModifiers())) {
-        if (instance == null) {
+        if (instance eq null) {
           instance = try {
             clazz.newInstance()
           } catch { case _ =>
@@ -202,7 +202,7 @@ class Code(clazz: java.lang.Class) {
         obj = instance
       }
       val result = method.invoke(obj, args)
-      if (result == null) ().asInstanceOf[JObject] else result
+      if (result eq null) ().asInstanceOf[JObject] else result
     }
     catch {
       case me: NoSuchMethodException =>
diff --git a/src/library/scala/mobile/Location.scala b/src/library/scala/mobile/Location.scala
index 246db26fc9..2b8d456ea5 100644
--- a/src/library/scala/mobile/Location.scala
+++ b/src/library/scala/mobile/Location.scala
@@ -41,7 +41,7 @@ class Location(url: URL) {
 
   /** The class loader associated with this location.
    */
-  private val loader = if (url == null)
+  private val loader = if (url eq null)
     ClassLoader.getSystemClassLoader()
   else
     lcache.get(url) match {
diff --git a/src/library/scala/runtime/BoxedAnyArray.scala b/src/library/scala/runtime/BoxedAnyArray.scala
index 558c01dead..7242e5763a 100644
--- a/src/library/scala/runtime/BoxedAnyArray.scala
+++ b/src/library/scala/runtime/BoxedAnyArray.scala
@@ -28,7 +28,7 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
   private var elemClass: Class = null
 
   def apply(index: Int): AnyRef = synchronized {
-    if (unboxed == null)
+    if (unboxed eq null)
       boxed(index);
     else if (elemClass eq ScalaRunTime.IntTYPE)
       Int.box(unboxed.asInstanceOf[Array[Int]](index))
@@ -51,7 +51,7 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
   }
 
   def update(index: Int, elem: AnyRef): Unit = synchronized {
-    if (unboxed == null)
+    if (unboxed eq null)
       boxed(index) = elem
     else if (elemClass eq ScalaRunTime.IntTYPE)
       unboxed.asInstanceOf[Array[Int]](index) = Int.unbox(elem)
@@ -85,7 +85,7 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
     else unbox(Platform.getClassForName(elemTag))
 
   def unbox(elemClass: Class): AnyRef = synchronized {
-    if (unboxed == null) {
+    if (unboxed eq null) {
       this.elemClass = elemClass;
       if (elemClass eq ScalaRunTime.IntTYPE) {
 	val newvalue = new Array[Int](length)
@@ -165,21 +165,21 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
 
   override def equals(other: Any): Boolean = (
     other.isInstanceOf[BoxedAnyArray] && (this eq (other.asInstanceOf[BoxedAnyArray])) ||
-    (if (unboxed == null) boxed == other else unboxed == other)
+    (if (unboxed eq null) boxed == other else unboxed == other)
   )
 
   override def hashCode(): Int = hash
 
   def value: AnyRef = {
-    if (unboxed == null) throw new NotDefinedError("BoxedAnyArray.value")
+    if (unboxed eq null) throw new NotDefinedError("BoxedAnyArray.value")
     unboxed
   }
 
   private def adapt(other: AnyRef): AnyRef =
-    if (this.unboxed == null)
+    if (this.unboxed eq null)
       other match {
         case that: BoxedAnyArray =>
-          if (that.unboxed == null) {
+          if (that.unboxed eq null) {
             that.boxed
           } else {
             if (ScalaRunTime.isValueClass(that.elemClass)) unbox(that.elemClass);
@@ -209,7 +209,7 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
     else
       other match {
         case that: BoxedAnyArray =>
-          if (that.unboxed != null) that.unboxed
+          if (that.unboxed ne null) that.unboxed
           else if (ScalaRunTime.isValueClass(this.elemClass)) that.unbox(this.elemClass)
           else that.boxed
         case that: BoxedArray =>
@@ -220,12 +220,12 @@ final class BoxedAnyArray(val length: Int) extends BoxedArray {
 
   override def copyFrom(src: AnyRef, from: Int, to: Int, len: Int): Unit = {
     val src1 = adapt(src)
-    Array.copy(src1, from, if (unboxed != null) unboxed else boxed, to, len)
+    Array.copy(src1, from, if (unboxed ne null) unboxed else boxed, to, len)
   }
 
   override def copyTo(from: Int, dest: AnyRef, to: Int, len: Int): Unit = {
     var dest1 = adapt(dest)
-    Array.copy(if (unboxed != null) unboxed else boxed, from, dest1, to, len)
+    Array.copy(if (unboxed ne null) unboxed else boxed, from, dest1, to, len)
   }
 
   override def subArray(start: Int, end: Int): AnyRef = {
diff --git a/src/library/scala/runtime/ScalaRunTime.scala b/src/library/scala/runtime/ScalaRunTime.scala
index 7173253316..f0b5eb3ddc 100644
--- a/src/library/scala/runtime/ScalaRunTime.scala
+++ b/src/library/scala/runtime/ScalaRunTime.scala
@@ -52,7 +52,7 @@ object ScalaRunTime {
     def run(): Unit = result = block;
 
     def Catch[b >: a](handler: PartialFunction[Throwable, b]): b =
-      if (exception == null)
+      if (exception eq null)
 	result.asInstanceOf[b]
       // !!! else if (exception is LocalReturn)
       // !!!   // ...
@@ -62,7 +62,7 @@ object ScalaRunTime {
 	throw exception;
 
     def Finally(handler: Unit): a =
-      if (exception == null)
+      if (exception eq null)
         result.asInstanceOf[a]
       else
         throw exception;
diff --git a/src/library/scala/xml/Elem.scala b/src/library/scala/xml/Elem.scala
index 96b571c505..77941f1c60 100644
--- a/src/library/scala/xml/Elem.scala
+++ b/src/library/scala/xml/Elem.scala
@@ -28,7 +28,7 @@ case class Elem(override val prefix: String,
                 override val scope: NamespaceBinding,
                 val child: Node*) extends Node {
 
-  if (prefix != null && 0 == prefix.length())
+  if ((null != prefix) && 0 == prefix.length())
     throw new IllegalArgumentException("prefix of zero length, use null instead");
 
   if (null == scope)
diff --git a/src/library/scala/xml/NamespaceBinding.scala b/src/library/scala/xml/NamespaceBinding.scala
index 0a3f860803..c1acb444e5 100644
--- a/src/library/scala/xml/NamespaceBinding.scala
+++ b/src/library/scala/xml/NamespaceBinding.scala
@@ -59,7 +59,7 @@ class NamespaceBinding(val prefix: String,
   def toString(sb: StringBuilder, stop: NamespaceBinding): Unit = {
     if (this ne stop) { // contains?
       sb.append(" xmlns")
-      if (prefix != null) {
+      if (prefix ne null) {
         sb.append(':').append(prefix)
       }
       sb.append('=')
diff --git a/src/library/scala/xml/Node.scala b/src/library/scala/xml/Node.scala
index 141a9f9f1b..e9d233af13 100644
--- a/src/library/scala/xml/Node.scala
+++ b/src/library/scala/xml/Node.scala
@@ -67,7 +67,7 @@ abstract class Node extends NodeSeq {
    * @return    the namespace if <code>scope != null</code> and prefix was
    *            found, else <code>null</code>
    */
-  def getNamespace(pre: String) = if (scope == null) null else scope.getURI(pre)
+  def getNamespace(pre: String) = if (scope eq null) null else scope.getURI(pre)
 
   /**
    * Convenience method, looks up an unprefixed attribute in attributes of this node.
diff --git a/src/library/scala/xml/PrefixedAttribute.scala b/src/library/scala/xml/PrefixedAttribute.scala
index 96ba45c73c..397a68507c 100644
--- a/src/library/scala/xml/PrefixedAttribute.scala
+++ b/src/library/scala/xml/PrefixedAttribute.scala
@@ -21,7 +21,7 @@ class PrefixedAttribute(val pre: String,
                         val value: Seq[Node],
                         val next: MetaData) extends MetaData {
 
-  if(value == null)
+  if(value eq null)
     throw new UnsupportedOperationException("value is null")
 
   /** same as this(key, Utility.parseAttributeValue(value), next) */
@@ -71,7 +71,7 @@ class PrefixedAttribute(val pre: String,
 
 
   /** appends string representation of only this attribute to stringbuffer */
-  def toString1(sb:StringBuilder): Unit = if(value!=null) {
+  def toString1(sb:StringBuilder): Unit = if(value ne null) {
     sb.append(pre)
     sb.append(':')
     sb.append(key)
diff --git a/src/library/scala/xml/UnprefixedAttribute.scala b/src/library/scala/xml/UnprefixedAttribute.scala
index 5159c5a67f..8f08da3696 100644
--- a/src/library/scala/xml/UnprefixedAttribute.scala
+++ b/src/library/scala/xml/UnprefixedAttribute.scala
@@ -18,11 +18,11 @@ import compat.StringBuilder
  */
 class UnprefixedAttribute(val key: String, val value: Seq[Node], next1: MetaData) extends MetaData {
 
-  val next = if(value != null) next1 else next1.remove(key)
+  val next = if(value ne null) next1 else next1.remove(key)
 
   /** same as this(key, Utility.parseAttributeValue(value), next) */
   def this(key: String, value: String, next: MetaData) =
-    this(key, if(value!=null) Text(value) else {val z:NodeSeq=null;z}, next)
+    this(key, if(value ne null) Text(value) else {val z:NodeSeq=null;z}, next)
 
   /** returns a copy of this unprefixed attribute with the given next field*/
   def copy(next: MetaData) =
@@ -58,13 +58,13 @@ class UnprefixedAttribute(val key: String, val value: Seq[Node], next1: MetaData
   /** returns the hashcode.
    */
   override def hashCode() =
-    key.hashCode() * 7 + { if(value!=null) value.hashCode() * 53 else 0 } + next.hashCode()
+    key.hashCode() * 7 + { if(value ne null) value.hashCode() * 53 else 0 } + next.hashCode()
 
   /** returns false */
   final def isPrefixed = false
 
   /** appends string representation of only this attribute to stringbuffer */
-  def toString1(sb:StringBuilder): Unit = if(value!=null) {
+  def toString1(sb:StringBuilder): Unit = if(value ne null) {
     sb.append(key)
     sb.append('=')
     val sb2 = new StringBuilder()
diff --git a/src/library/scala/xml/Utility.scala b/src/library/scala/xml/Utility.scala
index fdc6681b5c..2788fd9529 100644
--- a/src/library/scala/xml/Utility.scala
+++ b/src/library/scala/xml/Utility.scala
@@ -159,7 +159,7 @@ object Utility extends AnyRef with parsing.TokenTests {
         // print tag with namespace declarations
         sb.append('<')
         x.nameToString(sb)
-        if (x.attributes != null) {
+        if (x.attributes ne null) {
           x.attributes.toString(sb)
         }
         x.scope.toString(sb, pscope)
@@ -215,7 +215,7 @@ object Utility extends AnyRef with parsing.TokenTests {
    * @param children
    */
   def hashCode(pre: String, label: String, attribHashCode: Int, scpeHash: Int, children: Seq[Node]) = {
-    ( if(pre!=null) {41 * pre.hashCode() % 7} else {0})
+    ( if(pre ne null) {41 * pre.hashCode() % 7} else {0})
     + label.hashCode() * 53
     + attribHashCode * 7
     + scpeHash * 31
@@ -337,7 +337,7 @@ object Utility extends AnyRef with parsing.TokenTests {
           return "< not allowed in attribute value";
         case '&' =>
           val n = getName(value, i+1);
-          if (n == null)
+          if (n eq null)
             return "malformed entity reference in attribute value ["+value+"]";
           i = i + n.length() + 1
           if (i >= value.length() || value.charAt(i) != ';')
@@ -372,7 +372,7 @@ object Utility extends AnyRef with parsing.TokenTests {
               sb.append(theChar)
 
             case x =>
-              if (rfb==null) rfb = new StringBuilder()
+              if (rfb eq null) rfb = new StringBuilder()
               rfb.append(x)
               c = it.next
               while (c != ';') {
diff --git a/src/library/scala/xml/XML.scala b/src/library/scala/xml/XML.scala
index 673c44d333..e9e51ca520 100644
--- a/src/library/scala/xml/XML.scala
+++ b/src/library/scala/xml/XML.scala
@@ -151,7 +151,7 @@ object XML  {
   final def write(w: java.io.Writer, node: Node, enc: String, xmlDecl: Boolean, doctype: dtd.DocType): Unit = {
     /* TODO: optimize by giving writer parameter to toXML*/
     if (xmlDecl) w.write("<?xml version='1.0' encoding='" + enc + "'?>\n")
-    if (doctype != null) w.write( doctype.toString() + "\n")
+    if (doctype ne null) w.write( doctype.toString() + "\n")
     w.write(Utility.toXML(node))
   }
 }
diff --git a/src/library/scala/xml/dtd/ElementValidator.scala b/src/library/scala/xml/dtd/ElementValidator.scala
index 19406c577d..645caa66eb 100644
--- a/src/library/scala/xml/dtd/ElementValidator.scala
+++ b/src/library/scala/xml/dtd/ElementValidator.scala
@@ -57,7 +57,7 @@ class ElementValidator() extends Function1[Node,Boolean] {
 
             }
             case _ =>
-              x.namespace == null
+              x.namespace eq null
           }}
           . map { x => ElemName(x.label) }
           . elements;
diff --git a/src/library/scala/xml/dtd/ExternalID.scala b/src/library/scala/xml/dtd/ExternalID.scala
index 304c8b01e0..514db9c60f 100644
--- a/src/library/scala/xml/dtd/ExternalID.scala
+++ b/src/library/scala/xml/dtd/ExternalID.scala
@@ -66,7 +66,7 @@ case class PublicID( publicId:String, systemId:String ) extends ExternalID with
     throw new IllegalArgumentException(
       "publicId must consist of PubidChars"
     )
-  if( systemId != null && !checkSysID( systemId ) )
+  if( (systemId ne null) && !checkSysID( systemId ) )
     throw new IllegalArgumentException(
       "can't use both \" and ' in systemId"
     )
@@ -83,7 +83,7 @@ case class PublicID( publicId:String, systemId:String ) extends ExternalID with
   /** appends "PUBLIC "+publicId+" SYSTEM "+systemId to argument */
   override def toString(sb: StringBuilder): StringBuilder = {
     Utility.publicLiteralToString( sb, publicId ).append(' ')
-    if(systemId!=null)
+    if(systemId ne null)
       Utility.systemLiteralToString( sb, systemId )
     else
       sb
diff --git a/src/library/scala/xml/parsing/ExternalSources.scala b/src/library/scala/xml/parsing/ExternalSources.scala
index d3fd41314d..90b7f406a4 100644
--- a/src/library/scala/xml/parsing/ExternalSources.scala
+++ b/src/library/scala/xml/parsing/ExternalSources.scala
@@ -30,7 +30,7 @@ trait ExternalSources requires (ExternalSources with MarkupParser with MarkupHan
     var inputLine:String = null;
 
     //while (inputLine = in.readLine()) != null) {
-    while ({inputLine = in.readLine(); inputLine} != null) {
+    while ({inputLine = in.readLine(); inputLine} ne null) {
       // Console.println(inputLine); // DEBUG
       str.append(inputLine);
       str.append('\n'); // readable output
diff --git a/src/library/scala/xml/parsing/FactoryAdapter.scala b/src/library/scala/xml/parsing/FactoryAdapter.scala
index 99d81aef72..d1deabb5a2 100644
--- a/src/library/scala/xml/parsing/FactoryAdapter.scala
+++ b/src/library/scala/xml/parsing/FactoryAdapter.scala
@@ -188,7 +188,7 @@ abstract class FactoryAdapter extends DefaultHandler() {
     // reverse order to get it right
     var v: List[Node] = Nil
     var child: Node = hStack.pop
-    while (child != null) {
+    while (child ne null) {
       v = child::v
       child = hStack.pop
     }
@@ -209,7 +209,7 @@ abstract class FactoryAdapter extends DefaultHandler() {
     curTag = tagStack.pop
 
     capture =
-      if (curTag != null) nodeContainsText(curTag) // root level
+      if (curTag ne null) nodeContainsText(curTag) // root level
       else false
   } // endElement(String,String,String)
 
@@ -243,7 +243,7 @@ abstract class FactoryAdapter extends DefaultHandler() {
     Console.print("] ")
 
     var systemId = ex.getSystemId()
-    if (systemId != null) {
+    if (systemId ne null) {
       val index = systemId.lastIndexOf('/'.asInstanceOf[Int])
       if (index != -1)
         systemId = systemId.substring(index + 1)
diff --git a/src/library/scala/xml/parsing/MarkupParser.scala b/src/library/scala/xml/parsing/MarkupParser.scala
index c3a69b555a..e1813fdac5 100644
--- a/src/library/scala/xml/parsing/MarkupParser.scala
+++ b/src/library/scala/xml/parsing/MarkupParser.scala
@@ -580,7 +580,7 @@ trait MarkupParser requires (MarkupParser with MarkupHandler) extends AnyRef wit
   def parseDTD(): Unit = { // dirty but fast
     //Console.println("(DEBUG) parseDTD");
     var extID: ExternalID = null
-    if (this.dtd != null)
+    if (this.dtd ne null)
       reportSyntaxError("unexpected character (DOCTYPE already defined");
     xToken("DOCTYPE")
     xSpace
@@ -649,7 +649,7 @@ trait MarkupParser requires (MarkupParser with MarkupHandler) extends AnyRef wit
       /*override val */decls      = handle.decls.reverse
     }
     //this.dtd.initializeEntities();
-    if (doc!=null)
+    if (doc ne null)
       doc.dtd = this.dtd
 
     handle.endDTD(n)
diff --git a/src/library/scala/xml/pull/XMLEventReader.scala b/src/library/scala/xml/pull/XMLEventReader.scala
index b89bdb764d..130d7afe19 100644
--- a/src/library/scala/xml/pull/XMLEventReader.scala
+++ b/src/library/scala/xml/pull/XMLEventReader.scala
@@ -59,7 +59,7 @@ class XMLEventReader extends Iterator[XMLEvent] {
     notifyAll
   }
   def getAndClearEvent: XMLEvent = synchronized {
-    while(xmlEvent == null) {
+    while(xmlEvent eq null) {
       wait()
     }
     val r = xmlEvent