diff --git a/config/android-checkstyle.gradle b/config/android-checkstyle.gradle
new file mode 100644
index 00000000..f998530e
--- /dev/null
+++ b/config/android-checkstyle.gradle
@@ -0,0 +1,28 @@
+apply plugin: 'checkstyle'
+check.dependsOn 'checkstyle'
+
+checkstyle {
+    toolVersion = '6.19'
+}
+
+task checkstyle(type: Checkstyle) {
+    description = "Check Java style with Checkstyle"
+    configFile = rootProject.file("config/checkstyle/checkstyle.xml")
+    source = javaSources()
+    classpath = files()
+    ignoreFailures = true
+}
+
+def javaSources() {
+    def files = []
+    android.sourceSets.each { sourceSet ->
+        sourceSet.java.each { javaSource ->
+            javaSource.getSrcDirs().each {
+                if (it.exists()) {
+                    files.add(it)
+                }
+            }
+        }
+    }
+    return files
+}
diff --git a/config/checkstyle/checkstyle.xml b/config/checkstyle/checkstyle.xml
new file mode 100644
index 00000000..63ee315a
--- /dev/null
+++ b/config/checkstyle/checkstyle.xml
@@ -0,0 +1,182 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC
+  "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+  "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+
+<!-- This is a checkstyle configuration file. For descriptions of
+what the following rules do, please see the checkstyle configuration
+page at http://checkstyle.sourceforge.net/config.html -->
+
+<module name="Checker">
+
+  <!-- Checks whether files end with a new line.                        -->
+  <!-- See http://checkstyle.sf.net/config_misc.html#NewlineAtEndOfFile -->
+  <module name="NewlineAtEndOfFile" />
+
+  <!-- Checks that property files contain the same keys.         -->
+  <!-- See http://checkstyle.sf.net/config_misc.html#Translation -->
+  <module name="Translation" />
+
+  <!-- Checks for Size Violations.                    -->
+  <!-- See http://checkstyle.sf.net/config_sizes.html -->
+  <module name="FileLength" />
+
+  <!-- Checks for whitespace                               -->
+  <!-- See http://checkstyle.sf.net/config_whitespace.html -->
+  <module name="FileTabCharacter" />
+
+  <!-- Miscellaneous other checks.                   -->
+  <!-- See http://checkstyle.sf.net/config_misc.html -->
+  <module name="RegexpSingleline">
+    <property name="format" value="\s+$" />
+    <property name="minimum" value="0" />
+    <property name="maximum" value="0" />
+    <property name="message" value="Line has trailing spaces." />
+    <property name="severity" value="info" />
+  </module>
+
+  <module name="SuppressWarningsFilter"/>
+
+  <module name="TreeWalker">
+
+    <!-- Checks for Naming Conventions.                  -->
+    <!-- See http://checkstyle.sf.net/config_naming.html -->
+    <module name="ConstantName" />
+    <module name="LocalFinalVariableName" />
+    <module name="LocalVariableName" />
+    <module name="MemberName" />
+    <module name="MethodName" />
+    <module name="PackageName" />
+    <module name="ParameterName" />
+    <module name="StaticVariableName" />
+    <module name="TypeName" />
+
+    <module name="SuppressWarningsHolder"/>
+
+    <!-- Checks for imports                              -->
+    <!-- See http://checkstyle.sf.net/config_import.html -->
+    <module name="AvoidStarImport">
+      <property name="allowStaticMemberImports" value="true" />
+    </module>
+    <module name="IllegalImport" />
+    <!-- defaults to sun.* packages -->
+    <module name="RedundantImport" />
+    <module name="UnusedImports" />
+    <module name="CustomImportOrder">
+        <property name="thirdPartyPackageRegExp" value=".*"/>
+        <property name="specialImportsRegExp" value="com.genymobile"/>
+        <property name="separateLineBetweenGroups" value="true"/>
+        <property name="customImportOrderRules" value="SPECIAL_IMPORTS###THIRD_PARTY_PACKAGE###STANDARD_JAVA_PACKAGE###STATIC"/>
+    </module>
+
+
+    <!-- Checks for Size Violations.                    -->
+    <!-- See http://checkstyle.sf.net/config_sizes.html -->
+    <module name="LineLength">
+      <!-- what is a good max value? -->
+      <property name="max" value="150" />
+      <!-- ignore lines like "$File: //depot/... $" -->
+      <property name="ignorePattern" value="\$File.*\$" />
+      <property name="severity" value="info" />
+    </module>
+    <module name="MethodLength" />
+    <module name="ParameterNumber">
+      <property name="ignoreOverriddenMethods" value="true"/>
+    </module>
+
+
+    <!-- Checks for whitespace                               -->
+    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
+    <module name="EmptyForIteratorPad" />
+    <module name="GenericWhitespace" />
+    <module name="MethodParamPad" />
+    <module name="NoWhitespaceAfter" />
+    <module name="NoWhitespaceBefore" />
+    <module name="OperatorWrap" />
+    <module name="ParenPad" />
+    <module name="TypecastParenPad" />
+    <module name="WhitespaceAfter" />
+    <module name="WhitespaceAround" />
+
+    <!-- Modifier Checks                                    -->
+    <!-- See http://checkstyle.sf.net/config_modifiers.html -->
+    <module name="ModifierOrder" />
+    <module name="RedundantModifier" />
+
+
+    <!-- Checks for blocks. You know, those {}'s         -->
+    <!-- See http://checkstyle.sf.net/config_blocks.html -->
+    <module name="AvoidNestedBlocks" />
+    <module name="EmptyBlock">
+      <property name="option" value="text" />
+    </module>
+    <module name="LeftCurly" />
+    <module name="NeedBraces" />
+    <module name="RightCurly" />
+
+
+    <!-- Checks for common coding problems               -->
+    <!-- See http://checkstyle.sf.net/config_coding.html -->
+    <!-- <module name="AvoidInlineConditionals"/> -->
+    <module name="EmptyStatement" />
+    <module name="EqualsHashCode" />
+    <module name="HiddenField">
+      <property name="tokens" value="VARIABLE_DEF" />
+      <!-- only check variables not parameters -->
+      <property name="ignoreConstructorParameter" value="true" />
+      <property name="ignoreSetter" value="true" />
+      <property name="severity" value="warning" />
+    </module>
+    <module name="IllegalInstantiation" />
+    <module name="InnerAssignment" />
+    <module name="MagicNumber">
+      <property name="severity" value="info" />
+      <property name="ignoreHashCodeMethod" value="true" />
+      <property name="ignoreAnnotation" value="true" />
+    </module>
+    <module name="MissingSwitchDefault" />
+    <module name="SimplifyBooleanExpression" />
+    <module name="SimplifyBooleanReturn" />
+
+    <!-- Checks for class design                         -->
+    <!-- See http://checkstyle.sf.net/config_design.html -->
+    <!-- <module name="DesignForExtension"/> -->
+    <module name="FinalClass" />
+    <module name="HideUtilityClassConstructor" />
+    <module name="InterfaceIsType" />
+    <module name="VisibilityModifier" />
+
+
+    <!-- Miscellaneous other checks.                   -->
+    <!-- See http://checkstyle.sf.net/config_misc.html -->
+    <module name="ArrayTypeStyle" />
+    <!-- <module name="FinalParameters"/> -->
+    <module name="TodoComment">
+      <property name="format" value="TODO" />
+      <property name="severity" value="info" />
+    </module>
+    <module name="UpperEll" />
+
+    <module name="FileContentsHolder" />
+    <!-- Required by comment suppression filters -->
+
+  </module>
+
+  <module name="SuppressionFilter">
+    <!--<property name="file" value="team-props/checkstyle/checkstyle-suppressions.xml" />-->
+  </module>
+
+  <!-- Enable suppression comments -->
+  <module name="SuppressionCommentFilter">
+    <property name="offCommentFormat" value="CHECKSTYLE IGNORE\s+(\S+)" />
+    <property name="onCommentFormat" value="CHECKSTYLE END IGNORE\s+(\S+)" />
+    <property name="checkFormat" value="$1" />
+  </module>
+  <module name="SuppressWithNearbyCommentFilter">
+    <!-- Syntax is "SUPPRESS CHECKSTYLE name" -->
+    <property name="commentFormat" value="SUPPRESS CHECKSTYLE (\w+)" />
+    <property name="checkFormat" value="$1" />
+    <property name="influenceFormat" value="1" />
+  </module>
+
+</module>
diff --git a/server/build.gradle b/server/build.gradle
index c4ae50a1..0f3a6a9c 100644
--- a/server/build.gradle
+++ b/server/build.gradle
@@ -1,11 +1,11 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 26
+    compileSdkVersion 27
     defaultConfig {
         applicationId "com.genymobile.scrcpy"
         minSdkVersion 21
-        targetSdkVersion 26
+        targetSdkVersion 27
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -22,3 +22,5 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     testImplementation 'junit:junit:4.12'
 }
+
+apply from: "$project.rootDir/config/android-checkstyle.gradle"
diff --git a/server/src/main/java/com/genymobile/scrcpy/ControlEvent.java b/server/src/main/java/com/genymobile/scrcpy/ControlEvent.java
index 44d7cdd6..43b8f930 100644
--- a/server/src/main/java/com/genymobile/scrcpy/ControlEvent.java
+++ b/server/src/main/java/com/genymobile/scrcpy/ControlEvent.java
@@ -3,7 +3,7 @@ package com.genymobile.scrcpy;
 /**
  * Union of all supported event types, identified by their {@code type}.
  */
-public class ControlEvent {
+public final class ControlEvent {
 
     public static final int TYPE_KEYCODE = 0;
     public static final int TYPE_TEXT = 1;
diff --git a/server/src/main/java/com/genymobile/scrcpy/ControlEventReader.java b/server/src/main/java/com/genymobile/scrcpy/ControlEventReader.java
index 01a76d93..4d412f9b 100644
--- a/server/src/main/java/com/genymobile/scrcpy/ControlEventReader.java
+++ b/server/src/main/java/com/genymobile/scrcpy/ControlEventReader.java
@@ -12,9 +12,12 @@ public class ControlEventReader {
     private static final int SCROLL_PAYLOAD_LENGTH = 16;
     private static final int COMMAND_PAYLOAD_LENGTH = 1;
 
-    private final byte[] rawBuffer = new byte[128];
+    private static final int MAX_TEXT_LENGTH = 32;
+    private static final int RAW_BUFFER_SIZE = 128;
+
+    private final byte[] rawBuffer = new byte[RAW_BUFFER_SIZE];
     private final ByteBuffer buffer = ByteBuffer.wrap(rawBuffer);
-    private final byte[] textBuffer = new byte[32];
+    private final byte[] textBuffer = new byte[MAX_TEXT_LENGTH];
 
     public ControlEventReader() {
         // invariant: the buffer is always in "get" mode
@@ -136,10 +139,12 @@ public class ControlEventReader {
         return new Position(x, y, screenWidth, screenHeight);
     }
 
+    @SuppressWarnings("checkstyle:MagicNumber")
     private static int toUnsigned(short value) {
         return value & 0xffff;
     }
 
+    @SuppressWarnings("checkstyle:MagicNumber")
     private static int toUnsigned(byte value) {
         return value & 0xff;
     }
diff --git a/server/src/main/java/com/genymobile/scrcpy/DesktopConnection.java b/server/src/main/java/com/genymobile/scrcpy/DesktopConnection.java
index e739abe6..203ecc9b 100644
--- a/server/src/main/java/com/genymobile/scrcpy/DesktopConnection.java
+++ b/server/src/main/java/com/genymobile/scrcpy/DesktopConnection.java
@@ -9,7 +9,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 
-public class DesktopConnection implements Closeable {
+public final class DesktopConnection implements Closeable {
 
     private static final int DEVICE_NAME_FIELD_LENGTH = 64;
 
@@ -48,9 +48,8 @@ public class DesktopConnection implements Closeable {
         socket.close();
     }
 
+    @SuppressWarnings("checkstyle:MagicNumber")
     private void send(String deviceName, int width, int height) throws IOException {
-        assert width < 0x10000 : "width may not be stored on 16 bits";
-        assert height < 0x10000 : "height may not be stored on 16 bits";
         byte[] buffer = new byte[DEVICE_NAME_FIELD_LENGTH + 4];
 
         byte[] deviceNameBytes = deviceName.getBytes(StandardCharsets.UTF_8);
diff --git a/server/src/main/java/com/genymobile/scrcpy/Device.java b/server/src/main/java/com/genymobile/scrcpy/Device.java
index c6860a10..d78ea1b3 100644
--- a/server/src/main/java/com/genymobile/scrcpy/Device.java
+++ b/server/src/main/java/com/genymobile/scrcpy/Device.java
@@ -1,13 +1,13 @@
 package com.genymobile.scrcpy;
 
+import com.genymobile.scrcpy.wrappers.ServiceManager;
+
 import android.graphics.Point;
 import android.os.Build;
 import android.os.RemoteException;
 import android.view.IRotationWatcher;
 import android.view.InputEvent;
 
-import com.genymobile.scrcpy.wrappers.ServiceManager;
-
 public final class Device {
 
     public interface RotationListener {
@@ -40,6 +40,7 @@ public final class Device {
         return screenInfo;
     }
 
+    @SuppressWarnings("checkstyle:MagicNumber")
     private ScreenInfo computeScreenInfo(int maxSize) {
         // Compute the video size and the padding of the content inside this video.
         // Principle:
@@ -52,7 +53,9 @@ public final class Device {
         int w = deviceSize.getWidth();
         int h = deviceSize.getHeight();
         if (maxSize > 0) {
-            assert maxSize % 8 == 0;
+            if (BuildConfig.DEBUG && maxSize % 8 != 0) {
+                throw new AssertionError("Max size must be a multiple of 8");
+            }
             boolean portrait = h > w;
             int major = portrait ? h : w;
             int minor = portrait ? w : h;
@@ -70,6 +73,7 @@ public final class Device {
     }
 
     public Point getPhysicalPoint(Position position) {
+        @SuppressWarnings("checkstyle:HiddenField") // it hides the field on purpose, to read it with a lock
         ScreenInfo screenInfo = getScreenInfo(); // read with synchronization
         Size videoSize = screenInfo.getVideoSize();
         Size clientVideoSize = position.getScreenSize();
diff --git a/server/src/main/java/com/genymobile/scrcpy/EventController.java b/server/src/main/java/com/genymobile/scrcpy/EventController.java
index 6d2ec3dd..0af1aed8 100644
--- a/server/src/main/java/com/genymobile/scrcpy/EventController.java
+++ b/server/src/main/java/com/genymobile/scrcpy/EventController.java
@@ -1,5 +1,7 @@
 package com.genymobile.scrcpy;
 
+import com.genymobile.scrcpy.wrappers.InputManager;
+
 import android.graphics.Point;
 import android.os.SystemClock;
 import android.view.InputDevice;
@@ -8,10 +10,9 @@ import android.view.KeyCharacterMap;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 
-import com.genymobile.scrcpy.wrappers.InputManager;
-
 import java.io.IOException;
 
+
 public class EventController {
 
     private final Device device;
@@ -83,6 +84,8 @@ public class EventController {
             case ControlEvent.TYPE_COMMAND:
                 executeCommand(controlEvent.getAction());
                 break;
+            default:
+                // do nothing
         }
     }
 
@@ -157,6 +160,8 @@ public class EventController {
         switch (action) {
             case ControlEvent.COMMAND_SCREEN_ON:
                 return turnScreenOn();
+            default:
+                Ln.w("Unsupported command: " + action);
         }
         return false;
     }
diff --git a/server/src/main/java/com/genymobile/scrcpy/Ln.java b/server/src/main/java/com/genymobile/scrcpy/Ln.java
index 8cf52860..38269835 100644
--- a/server/src/main/java/com/genymobile/scrcpy/Ln.java
+++ b/server/src/main/java/com/genymobile/scrcpy/Ln.java
@@ -6,7 +6,7 @@ import android.util.Log;
  * Log both to Android logger (so that logs are visible in "adb logcat") and standard output/error (so that they are visible in the terminal
  * directly).
  */
-public class Ln {
+public final class Ln {
 
     private static final String TAG = "scrcpy";
 
diff --git a/server/src/main/java/com/genymobile/scrcpy/Position.java b/server/src/main/java/com/genymobile/scrcpy/Position.java
index 2e67b4f0..e00a6355 100644
--- a/server/src/main/java/com/genymobile/scrcpy/Position.java
+++ b/server/src/main/java/com/genymobile/scrcpy/Position.java
@@ -27,11 +27,15 @@ public class Position {
 
     @Override
     public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
         Position position = (Position) o;
-        return Objects.equals(point, position.point) &&
-                Objects.equals(screenSize, position.screenSize);
+        return Objects.equals(point, position.point)
+                && Objects.equals(screenSize, position.screenSize);
     }
 
     @Override
@@ -41,10 +45,10 @@ public class Position {
 
     @Override
     public String toString() {
-        return "Position{" +
-                "point=" + point +
-                ", screenSize=" + screenSize +
-                '}';
+        return "Position{"
+                + "point=" + point
+                + ", screenSize=" + screenSize
+                + '}';
     }
 
 }
diff --git a/server/src/main/java/com/genymobile/scrcpy/ScrCpyServer.java b/server/src/main/java/com/genymobile/scrcpy/ScrCpyServer.java
index cfe508ba..f4dd793f 100644
--- a/server/src/main/java/com/genymobile/scrcpy/ScrCpyServer.java
+++ b/server/src/main/java/com/genymobile/scrcpy/ScrCpyServer.java
@@ -2,7 +2,11 @@ package com.genymobile.scrcpy;
 
 import java.io.IOException;
 
-public class ScrCpyServer {
+public final class ScrCpyServer {
+
+    private ScrCpyServer() {
+        // not instantiable
+    }
 
     private static void scrcpy(Options options) throws IOException {
         final Device device = new Device(options);
@@ -34,6 +38,7 @@ public class ScrCpyServer {
         }).start();
     }
 
+    @SuppressWarnings("checkstyle:MagicNumber")
     private static Options createOptions(String... args) {
         Options options = new Options();
         if (args.length < 1) {
diff --git a/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java b/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java
index 2d056351..6aa0c276 100644
--- a/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java
+++ b/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java
@@ -1,5 +1,7 @@
 package com.genymobile.scrcpy;
 
+import com.genymobile.scrcpy.wrappers.SurfaceControl;
+
 import android.graphics.Rect;
 import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
@@ -7,8 +9,6 @@ import android.media.MediaFormat;
 import android.os.IBinder;
 import android.view.Surface;
 
-import com.genymobile.scrcpy.wrappers.SurfaceControl;
-
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
@@ -22,6 +22,8 @@ public class ScreenEncoder implements Device.RotationListener {
 
     private static final int REPEAT_FRAME_DELAY = 6; // repeat after 6 frames
 
+    private static final int MICROSECONDS_IN_ONE_SECOND = 1_000_000;
+
     private final AtomicBoolean rotationChanged = new AtomicBoolean();
 
     private int bitRate;
@@ -81,6 +83,7 @@ public class ScreenEncoder implements Device.RotationListener {
     }
 
     private boolean encode(MediaCodec codec, OutputStream outputStream) throws IOException {
+        @SuppressWarnings("checkstyle:MagicNumber")
         byte[] buf = new byte[bitRate / 8]; // may contain up to 1 second of video
         boolean eof = false;
         MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
@@ -124,7 +127,7 @@ public class ScreenEncoder implements Device.RotationListener {
         format.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
         format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, iFrameInterval);
         // display the very first frame, and recover from bad quality when no new frames
-        format.setLong(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER, 1_000_000 * REPEAT_FRAME_DELAY / frameRate); // µs
+        format.setLong(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER, MICROSECONDS_IN_ONE_SECOND * REPEAT_FRAME_DELAY / frameRate); // µs
         return format;
     }
 
diff --git a/server/src/main/java/com/genymobile/scrcpy/Size.java b/server/src/main/java/com/genymobile/scrcpy/Size.java
index 96026d87..0d546bbd 100644
--- a/server/src/main/java/com/genymobile/scrcpy/Size.java
+++ b/server/src/main/java/com/genymobile/scrcpy/Size.java
@@ -31,11 +31,15 @@ public final class Size {
 
     @Override
     public boolean equals(Object o) {
-        if (this == o) return true;
-        if (o == null || getClass() != o.getClass()) return false;
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
         Size size = (Size) o;
-        return width == size.width &&
-                height == size.height;
+        return width == size.width
+                && height == size.height;
     }
 
     @Override
@@ -45,9 +49,9 @@ public final class Size {
 
     @Override
     public String toString() {
-        return "Size{" +
-                "width=" + width +
-                ", height=" + height +
-                '}';
+        return "Size{"
+                + "width=" + width
+                + ", height=" + height
+                + '}';
     }
 }
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java
index 99dcf258..568afacd 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/DisplayManager.java
@@ -1,11 +1,11 @@
 package com.genymobile.scrcpy.wrappers;
 
-import android.os.IInterface;
-
 import com.genymobile.scrcpy.DisplayInfo;
 import com.genymobile.scrcpy.Size;
 
-public class DisplayManager {
+import android.os.IInterface;
+
+public final class DisplayManager {
     private final IInterface manager;
 
     public DisplayManager(IInterface manager) {
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java
index d34f6f59..1fc78c27 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java
@@ -6,7 +6,7 @@ import android.view.InputEvent;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 
-public class InputManager {
+public final class InputManager {
 
     public static final int INJECT_INPUT_EVENT_MODE_ASYNC = 0;
     public static final int INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT = 1;
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/PowerManager.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/PowerManager.java
index b53add80..a730d1b1 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/PowerManager.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/PowerManager.java
@@ -1,19 +1,21 @@
 package com.genymobile.scrcpy.wrappers;
 
+import android.annotation.SuppressLint;
 import android.os.Build;
 import android.os.IInterface;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 
-public class PowerManager {
+public final class PowerManager {
     private final IInterface manager;
     private final Method isScreenOnMethod;
 
     public PowerManager(IInterface manager) {
         this.manager = manager;
         try {
-            String methodName = Build.VERSION.SDK_INT >= 20 ? "isInteractive" : "isScreenOn";
+            @SuppressLint("ObsoleteSdkInt") // we may lower minSdkVersion in the future
+            String methodName = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH ? "isInteractive" : "isScreenOn";
             isScreenOnMethod = manager.getClass().getMethod(methodName);
         } catch (NoSuchMethodException e) {
             throw new AssertionError(e);
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java
index 4952893d..2d98d0a8 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java
@@ -1,11 +1,13 @@
 package com.genymobile.scrcpy.wrappers;
 
+import android.annotation.SuppressLint;
 import android.os.IBinder;
 import android.os.IInterface;
 
 import java.lang.reflect.Method;
 
-public class ServiceManager {
+@SuppressLint("PrivateApi")
+public final class ServiceManager {
     private final Method getServiceMethod;
 
     private WindowManager windowManager;
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java
index 35efbc27..85733867 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java
@@ -1,16 +1,18 @@
 package com.genymobile.scrcpy.wrappers;
 
+import android.annotation.SuppressLint;
 import android.graphics.Rect;
 import android.os.IBinder;
 import android.view.Surface;
 
-public class SurfaceControl {
+@SuppressLint("PrivateApi")
+public final class SurfaceControl {
 
-    private static final Class<?> cls;
+    private static final Class<?> CLASS;
 
     static {
         try {
-            cls = Class.forName("android.view.SurfaceControl");
+            CLASS = Class.forName("android.view.SurfaceControl");
         } catch (ClassNotFoundException e) {
             throw new AssertionError(e);
         }
@@ -22,7 +24,7 @@ public class SurfaceControl {
 
     public static void openTransaction() {
         try {
-            cls.getMethod("openTransaction").invoke(null);
+            CLASS.getMethod("openTransaction").invoke(null);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
@@ -30,7 +32,7 @@ public class SurfaceControl {
 
     public static void closeTransaction() {
         try {
-            cls.getMethod("closeTransaction").invoke(null);
+            CLASS.getMethod("closeTransaction").invoke(null);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
@@ -38,7 +40,7 @@ public class SurfaceControl {
 
     public static void setDisplayProjection(IBinder displayToken, int orientation, Rect layerStackRect, Rect displayRect) {
         try {
-            cls.getMethod("setDisplayProjection", IBinder.class, int.class, Rect.class, Rect.class)
+            CLASS.getMethod("setDisplayProjection", IBinder.class, int.class, Rect.class, Rect.class)
                     .invoke(null, displayToken, orientation, layerStackRect, displayRect);
         } catch (Exception e) {
             throw new AssertionError(e);
@@ -47,7 +49,7 @@ public class SurfaceControl {
 
     public static void setDisplayLayerStack(IBinder displayToken, int layerStack) {
         try {
-            cls.getMethod("setDisplayLayerStack", IBinder.class, int.class).invoke(null, displayToken, layerStack);
+            CLASS.getMethod("setDisplayLayerStack", IBinder.class, int.class).invoke(null, displayToken, layerStack);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
@@ -55,7 +57,7 @@ public class SurfaceControl {
 
     public static void setDisplaySurface(IBinder displayToken, Surface surface) {
         try {
-            cls.getMethod("setDisplaySurface", IBinder.class, Surface.class).invoke(null, displayToken, surface);
+            CLASS.getMethod("setDisplaySurface", IBinder.class, Surface.class).invoke(null, displayToken, surface);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
@@ -63,7 +65,7 @@ public class SurfaceControl {
 
     public static IBinder createDisplay(String name, boolean secure) {
         try {
-            return (IBinder) cls.getMethod("createDisplay", String.class, boolean.class).invoke(null, name, secure);
+            return (IBinder) CLASS.getMethod("createDisplay", String.class, boolean.class).invoke(null, name, secure);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
@@ -71,7 +73,7 @@ public class SurfaceControl {
 
     public static void destroyDisplay(IBinder displayToken) {
         try {
-            cls.getMethod("destroyDisplay", IBinder.class).invoke(null, displayToken);
+            CLASS.getMethod("destroyDisplay", IBinder.class).invoke(null, displayToken);
         } catch (Exception e) {
             throw new AssertionError(e);
         }
diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/WindowManager.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/WindowManager.java
index 78e50c3b..56330f9d 100644
--- a/server/src/main/java/com/genymobile/scrcpy/wrappers/WindowManager.java
+++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/WindowManager.java
@@ -3,7 +3,7 @@ package com.genymobile.scrcpy.wrappers;
 import android.os.IInterface;
 import android.view.IRotationWatcher;
 
-public class WindowManager {
+public final class WindowManager {
     private final IInterface manager;
 
     public WindowManager(IInterface manager) {