diff --git a/platform/util-rt/src/com/intellij/openapi/util/text/StringUtilRt.java b/platform/util-rt/src/com/intellij/openapi/util/text/StringUtilRt.java
index 8e165958667e..d122c5582cbf 100644
--- a/platform/util-rt/src/com/intellij/openapi/util/text/StringUtilRt.java
+++ b/platform/util-rt/src/com/intellij/openapi/util/text/StringUtilRt.java
@@ -1,28 +1,12 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.openapi.util.text;
 
-import com.intellij.util.Function;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
 
 /**
@@ -341,16 +325,6 @@ public class StringUtilRt {
     return true;
   }
 
-  @NotNull
-  @Contract(pure = true)
-  public static <T> Function<T, String> createToStringFunction() {
-    return new Function<T, String>() {
-      public String fun(@NotNull T o) {
-        return o.toString();
-      }
-    };
-  }
-
   @NotNull
   @Contract(pure = true)
   public static String notNullize(@Nullable String s) {
@@ -363,44 +337,6 @@ public class StringUtilRt {
     return s == null ? defaultValue : s;
   }
 
-  @NotNull
-  @Contract(pure = true)
-  public static <T> String join(@NotNull Collection<? extends T> items,
-                                @NotNull Function<? super T, String> f,
-                                @NotNull String separator) {
-    if (items.isEmpty()) return "";
-    if (items.size() == 1) return notNullize(f.fun(items.iterator().next()));
-    return join((Iterable<? extends T>)items, f, separator);
-  }
-
-  @NotNull
-  @Contract(pure = true)
-  public static <T> String join(@NotNull Iterable<? extends T> items,
-                                @NotNull Function<? super T, String> f,
-                                @NotNull String separator) {
-    final StringBuilder result = new StringBuilder();
-    join(items, f, separator, result);
-    return result.toString();
-  }
-
-  public static <T> void join(@NotNull Iterable<? extends T> items,
-                              @NotNull Function<? super T, String> f,
-                              @NotNull String separator,
-                              @NotNull StringBuilder result) {
-    boolean isFirst = true;
-    for (T item : items) {
-      String string = f.fun(item);
-      if (string != null && string.length() > 0) {
-        if (isFirst) {
-          isFirst = false;
-        } else {
-          result.append(separator);
-        }
-        result.append(string);
-      }
-    }
-  }
-
   @NotNull
   @Contract(pure = true)
   public static List<String> splitHonorQuotes(@NotNull String s, char separator) {
@@ -523,14 +459,11 @@ public class StringUtilRt {
     return sb.toString();
   }
 
-  private static boolean isQuoteAt(@NotNull String s, int ind) {
-    char ch = s.charAt(ind);
-    return ch == '\'' || ch == '\"';
-  }
-
   @Contract(pure = true)
   public static boolean isQuotedString(@NotNull String s) {
-    return s.length() > 1 && isQuoteAt(s, 0) && s.charAt(0) == s.charAt(s.length() - 1);
+    return s.length() > 1 &&
+           (s.charAt(0) == '\'' || s.charAt(0) == '\"') &&
+           s.charAt(0) == s.charAt(s.length() - 1);
   }
 
   @NotNull
diff --git a/platform/util/src/com/intellij/openapi/util/text/StringUtil.java b/platform/util/src/com/intellij/openapi/util/text/StringUtil.java
index 381ecd0e6c6a..d849e7875179 100644
--- a/platform/util/src/com/intellij/openapi/util/text/StringUtil.java
+++ b/platform/util/src/com/intellij/openapi/util/text/StringUtil.java
@@ -121,7 +121,11 @@ public class StringUtil extends StringUtilRt {
   @NotNull
   @Contract(pure = true)
   public static <T> Function<T, String> createToStringFunction(@SuppressWarnings("unused") @NotNull Class<T> cls) {
-    return StringUtilRt.createToStringFunction();
+    return new Function<T, String>() {
+      public String fun(@NotNull T o) {
+        return o.toString();
+      }
+    };
   }
 
   @NotNull
@@ -1429,7 +1433,9 @@ public class StringUtil extends StringUtilRt {
   public static <T> String join(@NotNull Collection<? extends T> items,
                                 @NotNull Function<? super T, String> f,
                                 @NotNull String separator) {
-    return StringUtilRt.join(items, f, separator);
+    if (items.isEmpty()) return "";
+    if (items.size() == 1) return notNullize(f.fun(items.iterator().next()));
+    return join((Iterable<? extends T>)items, f, separator);
   }
 
   @Contract(pure = true)
@@ -1449,14 +1455,27 @@ public class StringUtil extends StringUtilRt {
   public static <T> String join(@NotNull Iterable<? extends T> items,
                                 @NotNull Function<? super T, String> f,
                                 @NotNull String separator) {
-    return StringUtilRt.join(items, f, separator);
+    StringBuilder result = new StringBuilder();
+    join(items, f, separator, result);
+    return result.toString();
   }
 
   public static <T> void join(@NotNull Iterable<? extends T> items,
                               @NotNull Function<? super T, String> f,
                               @NotNull String separator,
                               @NotNull StringBuilder result) {
-    StringUtilRt.join(items, f, separator, result);
+    boolean isFirst = true;
+    for (T item : items) {
+      String string = f.fun(item);
+      if (string != null && string.length() > 0) {
+        if (isFirst) {
+          isFirst = false;
+        } else {
+          result.append(separator);
+        }
+        result.append(string);
+      }
+    }
   }
 
   @NotNull