diff --git a/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetCallableDefinitionUsage.java b/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetCallableDefinitionUsage.java
index ae5d4c1cb52..52d2d34ae21 100644
--- a/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetCallableDefinitionUsage.java
+++ b/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetCallableDefinitionUsage.java
@@ -165,7 +165,7 @@ public class JetCallableDefinitionUsage<T extends PsiElement> extends JetUsageIn
     }
 
     @Override
-    public boolean processUsage(JetChangeInfo changeInfo, PsiElement element) {
+    public boolean processUsage(@NotNull JetChangeInfo changeInfo, @NotNull PsiElement element) {
         if (!(element instanceof JetNamedDeclaration)) return true;
 
         JetPsiFactory psiFactory = JetPsiFactory(element.getProject());
diff --git a/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.java b/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.kt
similarity index 52%
rename from idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.java
rename to idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.kt
index 118926c7b7a..b07bc8bca03 100644
--- a/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.java
+++ b/idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetUsageInfo.kt
@@ -14,30 +14,19 @@
  * limitations under the License.
  */
 
-package org.jetbrains.kotlin.idea.refactoring.changeSignature.usages;
+package org.jetbrains.kotlin.idea.refactoring.changeSignature.usages
 
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiReference;
-import com.intellij.usageView.UsageInfo;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.jetbrains.kotlin.idea.refactoring.changeSignature.JetChangeInfo;
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiReference
+import com.intellij.usageView.UsageInfo
+import org.jetbrains.kotlin.idea.refactoring.changeSignature.JetChangeInfo
 
-public abstract class JetUsageInfo<T extends PsiElement> extends UsageInfo {
-    public JetUsageInfo(@NotNull T element) {
-        super(element);
-    }
+public abstract class JetUsageInfo<T : PsiElement> : UsageInfo {
+    public constructor(element: T) : super(element)
+    public constructor(reference: PsiReference) : super(reference)
 
-    public JetUsageInfo(@NotNull PsiReference reference) {
-        super(reference);
-    }
+    @suppress("UNCHECKED_CAST")
+    override fun getElement() = super.getElement() as T?
 
-    @Nullable
-    @Override
-    public T getElement() {
-        //noinspection unchecked
-        return (T) super.getElement();
-    }
-
-    public abstract boolean processUsage(JetChangeInfo changeInfo, T element);
+    public abstract fun processUsage(changeInfo: JetChangeInfo, element: T): Boolean
 }