diff --git a/platform/util/src/com/intellij/openapi/util/DefaultJDOMExternalizer.java b/platform/util/src/com/intellij/openapi/util/DefaultJDOMExternalizer.java
index fbc5dc112a09..f56423b3ce72 100644
--- a/platform/util/src/com/intellij/openapi/util/DefaultJDOMExternalizer.java
+++ b/platform/util/src/com/intellij/openapi/util/DefaultJDOMExternalizer.java
@@ -1,17 +1,5 @@
 /*
- * Copyright 2000-2017 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;
 
@@ -138,27 +126,29 @@ public class DefaultJDOMExternalizer {
   }
 
   @Nullable
-  static String filterXMLCharacters(String value) {
-    if (value != null) {
-      StringBuilder builder = null;
-      for (int i=0; i<value.length();i++) {
-        char c = value.charAt(i);
-        if (Verifier.isXMLCharacter(c)) {
-          if (builder != null) {
-            builder.append(c);
-          }
-        }
-        else {
-          if (builder == null) {
-            builder = new StringBuilder(value.length()+5);
-            builder.append(value, 0, i);
-          }
+  static String filterXMLCharacters(@Nullable String value) {
+    if (value == null) {
+      return null;
+    }
+
+    StringBuilder builder = null;
+    for (int i=0; i<value.length();i++) {
+      char c = value.charAt(i);
+      if (Verifier.isXMLCharacter(c)) {
+        if (builder != null) {
+          builder.append(c);
         }
       }
-      if (builder != null) {
-        value = builder.toString();
+      else {
+        if (builder == null) {
+          builder = new StringBuilder(value.length()+5);
+          builder.append(value, 0, i);
+        }
       }
     }
+    if (builder != null) {
+      value = builder.toString();
+    }
     return value;
   }
 
diff --git a/platform/util/src/com/intellij/openapi/util/JDOMExternalizableStringList.java b/platform/util/src/com/intellij/openapi/util/JDOMExternalizableStringList.java
index cfce4b8d0f3a..27f90dded709 100644
--- a/platform/util/src/com/intellij/openapi/util/JDOMExternalizableStringList.java
+++ b/platform/util/src/com/intellij/openapi/util/JDOMExternalizableStringList.java
@@ -32,7 +32,7 @@ public class JDOMExternalizableStringList extends ArrayList<String> implements J
   public JDOMExternalizableStringList() {
   }
 
-  public JDOMExternalizableStringList(@NotNull Collection<? extends String> c) {
+  public JDOMExternalizableStringList(@NotNull Collection<String> c) {
     super(c);
   }
 
@@ -78,7 +78,7 @@ public class JDOMExternalizableStringList extends ArrayList<String> implements J
     writeList(this, element);
   }
 
-  public static void writeList(@NotNull List<String> strings, @NotNull Element element) {
+  private static void writeList(@NotNull List<String> strings, @NotNull Element element) {
     int listSize = strings.size();
     Element listElement = new Element(ATTR_LIST);
     listElement.setAttribute(ATTR_LISTSIZE, Integer.toString(listSize));
diff --git a/platform/util/testSrc/com/intellij/util/containers/ByteArrayQueueTest.java b/platform/util/testSrc/com/intellij/util/containers/ByteArrayQueueTest.java
index 4debfa178ef9..1295fd05980d 100644
--- a/platform/util/testSrc/com/intellij/util/containers/ByteArrayQueueTest.java
+++ b/platform/util/testSrc/com/intellij/util/containers/ByteArrayQueueTest.java
@@ -1,20 +1,22 @@
+/*
+ * 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.util.containers;
 
-import junit.framework.Assert;
+import static junit.framework.TestCase.assertEquals;
 
 /**
  * @author Sergey Simonchik
  */
 public class ByteArrayQueueTest {
-
   @org.junit.Test
   public void testSingleAdd() {
     ByteArrayQueue queue = new ByteArrayQueue(0);
     byte value = 1;
     queue.add(value);
-    Assert.assertEquals(1, queue.size());
-    Assert.assertEquals(value, queue.poll());
-    Assert.assertEquals(-1, queue.poll());
+    assertEquals(1, queue.size());
+    assertEquals(value, queue.poll());
+    assertEquals(-1, queue.poll());
   }
 
   @org.junit.Test
@@ -22,11 +24,11 @@ public class ByteArrayQueueTest {
     ByteArrayQueue queue = new ByteArrayQueue(4);
     byte[] buf = new byte[] {1, 2, 3, 4, 5};
     queue.addAll(buf);
-    Assert.assertEquals(queue.size(), buf.length);
+    assertEquals(queue.size(), buf.length);
     for (byte b : buf) {
-      Assert.assertEquals(b, queue.poll());
+      assertEquals(b, queue.poll());
     }
-    Assert.assertEquals(-1, queue.poll());
+    assertEquals(-1, queue.poll());
   }
 
   @org.junit.Test
@@ -34,24 +36,23 @@ public class ByteArrayQueueTest {
     ByteArrayQueue queue = new ByteArrayQueue(4);
     byte[] buf = new byte[] {1, 2, 3, 4, 5, 6, 7, 8};
     queue.addAll(buf);
-    Assert.assertEquals(queue.size(), buf.length);
-    Assert.assertEquals(buf[0], queue.poll());
-    Assert.assertEquals(buf[1], queue.poll());
+    assertEquals(queue.size(), buf.length);
+    assertEquals(buf[0], queue.poll());
+    assertEquals(buf[1], queue.poll());
     byte v = 9;
     queue.add(v);
     queue.add(v);
 
     queue.addAll(buf); // array resize with myHead > myTail
-    Assert.assertEquals(queue.size(), buf.length * 2);
+    assertEquals(queue.size(), buf.length * 2);
     for (int i = 2; i < buf.length; i++) {
-      Assert.assertEquals(buf[i], queue.poll());
+      assertEquals(buf[i], queue.poll());
     }
-    Assert.assertEquals(v, queue.poll());
-    Assert.assertEquals(v, queue.poll());
+    assertEquals(v, queue.poll());
+    assertEquals(v, queue.poll());
     for (byte b : buf) {
-      Assert.assertEquals(b, queue.poll());
+      assertEquals(b, queue.poll());
     }
-    Assert.assertEquals(-1, queue.poll());
+    assertEquals(-1, queue.poll());
   }
-
 }