Custom hashCode() implementation semantically identical to Object.hashCode(). This one is much faster since Object.hashCode() is native JNI call.

platform/lang-impl/src/com/intellij/openapi/roots/impl/OrderEntryBaseImpl.java

@@ -23,6 +23,10 @@ public abstract class OrderEntryBaseImpl extends RootModelComponentBase implemen
   private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.roots.impl.OrderEntryVeryBaseImpl");
 
   private int myIndex;
+  private static int _hc = 0;
+
+  @SuppressWarnings({"AssignmentToStaticFieldFromInstanceMethod"})
+  private final int hc = _hc++;
 
   protected OrderEntryBaseImpl(RootModelImpl rootModel) {
     super(rootModel);
@@ -40,4 +44,15 @@ public abstract class OrderEntryBaseImpl extends RootModelComponentBase implemen
   boolean sameType(OrderEntry that) {
     return getClass().equals(that.getClass());
   }
+
+  @Override
+  @SuppressWarnings({"EqualsWhichDoesntCheckParameterClass"})
+  public boolean equals(Object obj) {
+    return obj == this;
+  }
+
+  @Override
+  public int hashCode() {
+    return hc;
+  }
 }