diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
index 752ef58bce5b..60421ed33ff6 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
@@ -39,6 +39,7 @@ import org.jetbrains.annotations.NotNull;
 import java.io.IOException;
 import java.lang.ref.Reference;
 import java.lang.ref.WeakReference;
+import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -874,22 +875,22 @@ public class RangeMarkerTest extends LightPlatformTestCase {
   private static void printFailingSteps(List<Pair<RangeMarker, TextRange>> adds,
                                         List<Pair<RangeMarker, TextRange>> dels,
                                         List<Trinity<Integer, Integer, Integer>> edits) {
-    String s = "adds: ";
+    StringBuilder s = new StringBuilder("adds: ");
     for (Pair<RangeMarker, TextRange> c : adds) {
       TextRange t = c.second;
-      s += t.getStartOffset() + "," + t.getEndOffset() + ", ";
+      s.append(t.getStartOffset()).append(",").append(t.getEndOffset()).append(", ");
     }
 
-    s += "\nedits: ";
+    s.append("\nedits: ");
     for (Trinity<Integer, Integer, Integer> edit : edits) {
-      s += edit.first + "," + edit.second + "," + edit.third + ",  ";
+      s.append(edit.first).append(",").append(edit.second).append(",").append(edit.third).append(",  ");
     }
-    s += "\ndels: ";
+    s.append("\ndels: ");
 
     for (Pair<RangeMarker, TextRange> c : dels) {
       int index = adds.indexOf(c);
       assertSame(c, adds.get(index));
-      s += index + ", ";
+      s.append(index).append(", ");
     }
     System.err.println(s);
   }
@@ -1374,7 +1375,7 @@ public class RangeMarkerTest extends LightPlatformTestCase {
 
     String newText = "0123blah";
     WriteCommandAction.runWriteCommandAction(getProject(), (ThrowableComputable<Object, IOException>)()->{
-      vf.setBinaryContent(newText.getBytes("utf-8"));
+      vf.setBinaryContent(newText.getBytes(StandardCharsets.UTF_8));
       return null;
     });
 
diff --git a/platform/xdebugger-impl/src/com/intellij/xdebugger/attach/fs/LazyAttachVirtualFS.java b/platform/xdebugger-impl/src/com/intellij/xdebugger/attach/fs/LazyAttachVirtualFS.java
index 902ea75a43db..7327a698e4bf 100644
--- a/platform/xdebugger-impl/src/com/intellij/xdebugger/attach/fs/LazyAttachVirtualFS.java
+++ b/platform/xdebugger-impl/src/com/intellij/xdebugger/attach/fs/LazyAttachVirtualFS.java
@@ -3,7 +3,10 @@ package com.intellij.xdebugger.attach.fs;
 
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.io.FileUtil;
-import com.intellij.openapi.vfs.*;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.openapi.vfs.VirtualFileListener;
+import com.intellij.openapi.vfs.VirtualFileManager;
+import com.intellij.openapi.vfs.VirtualFileSystem;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.xdebugger.attach.EnvironmentAwareHost;
 import org.jetbrains.annotations.NonNls;
@@ -12,6 +15,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -129,6 +133,6 @@ public class LazyAttachVirtualFS extends VirtualFileSystem {
       return null;
     }
 
-    return new String(FileUtil.loadBytes(stream), CharsetToolkit.UTF8);
+    return new String(FileUtil.loadBytes(stream), StandardCharsets.UTF_8);
   }
 }
diff --git a/plugins/java-decompiler/engine/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java b/plugins/java-decompiler/engine/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
index 47609fae99c1..684249ef3b2b 100644
--- a/plugins/java-decompiler/engine/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
+++ b/plugins/java-decompiler/engine/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
@@ -172,7 +172,7 @@ public class ConsoleDecompiler implements IBytecodeProvider, IResultSaver {
   @Override
   public void saveClassFile(String path, String qualifiedName, String entryName, String content, int[] mapping) {
     File file = new File(getAbsolutePath(path), entryName);
-    try (Writer out = new OutputStreamWriter(new FileOutputStream(file), "UTF8")) {
+    try (Writer out = new OutputStreamWriter(new FileOutputStream(file), StandardCharsets.UTF_8)) {
       out.write(content);
     }
     catch (IOException ex) {
diff --git a/python/ipnb/src/org/jetbrains/plugins/ipnb/protocol/IpnbConnection.java b/python/ipnb/src/org/jetbrains/plugins/ipnb/protocol/IpnbConnection.java
index ee3344b48936..363aca03a0f1 100644
--- a/python/ipnb/src/org/jetbrains/plugins/ipnb/protocol/IpnbConnection.java
+++ b/python/ipnb/src/org/jetbrains/plugins/ipnb/protocol/IpnbConnection.java
@@ -122,7 +122,7 @@ public class IpnbConnection {
       if (myXsrf == null) {
         initXSRF(myURI.toString() + USER_PATH + "/" + username + TREE_PATH);
       }
-      final Boolean started = startJupyterNotebookServer(username);
+      final boolean started = startJupyterNotebookServer(username);
       if (!started) {
         throw new IOException(CANNOT_START_JUPYTER);
       }
@@ -469,8 +469,7 @@ public class IpnbConnection {
 
   @NotNull
   private static String getResponse(HttpURLConnection connection) throws IOException {
-    final BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"));
-    try {
+    try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8))) {
       final StringBuilder builder = new StringBuilder();
       char[] buffer = new char[4096];
       int n;
@@ -480,7 +479,6 @@ public class IpnbConnection {
       return builder.toString();
     }
     finally {
-      reader.close();
       connection.disconnect();
     }
   }