diff --git a/build.gradle b/build.gradle
index c2d5f98b5c..42cfe085ad 100644
--- a/build.gradle
+++ b/build.gradle
@@ -20,8 +20,8 @@ plugins {
     id 'visual-studio'
     id 'net.ltgt.errorprone' version '2.0.2' apply false
     id 'com.github.johnrengelman.shadow' version '7.1.2' apply false
-    id 'com.diffplug.spotless' version '6.1.2' apply false
-    id 'com.github.spotbugs' version '5.0.4' apply false
+    id 'com.diffplug.spotless' version '6.4.2' apply false
+    id 'com.github.spotbugs' version '5.0.6' apply false
 }
 
 wpilibVersioning.buildServerMode = project.hasProperty('buildServer')
diff --git a/shared/java/javacommon.gradle b/shared/java/javacommon.gradle
index a40938cad1..b21bad380e 100644
--- a/shared/java/javacommon.gradle
+++ b/shared/java/javacommon.gradle
@@ -120,7 +120,7 @@ task run(type: JavaExec) {
 build.dependsOn devClasses
 
 jacoco {
-    toolVersion = "0.8.7"
+    toolVersion = "0.8.8"
 }
 
 jacocoTestReport {
diff --git a/shared/java/javastyle.gradle b/shared/java/javastyle.gradle
index ffe344c3a6..6259c2a483 100644
--- a/shared/java/javastyle.gradle
+++ b/shared/java/javastyle.gradle
@@ -2,7 +2,7 @@ if (!project.hasProperty('skipJavaFormat')) {
     apply plugin: 'checkstyle'
 
     checkstyle {
-        toolVersion = "9.2"
+        toolVersion = "10.1"
         configDirectory = file("${project.rootDir}/styleguide")
         config = resources.text.fromFile(new File(configDirectory.get().getAsFile(), "checkstyle.xml"))
     }
@@ -10,7 +10,7 @@ if (!project.hasProperty('skipJavaFormat')) {
     apply plugin: 'pmd'
 
     pmd {
-        toolVersion = '6.41.0'
+        toolVersion = '6.44.0'
         consoleOutput = true
         reportsDir = file("$project.buildDir/reports/pmd")
         ruleSetFiles = files(new File(rootDir, "styleguide/pmd-ruleset.xml"))
diff --git a/wpilibc/src/main/native/include/frc/DriverStation.h b/wpilibc/src/main/native/include/frc/DriverStation.h
index 532c93a611..8a3149b96c 100644
--- a/wpilibc/src/main/native/include/frc/DriverStation.h
+++ b/wpilibc/src/main/native/include/frc/DriverStation.h
@@ -19,7 +19,7 @@ namespace frc {
  * Provide access to the network communication data to / from the Driver
  * Station.
  */
-class DriverStation {
+class DriverStation final {
  public:
   enum Alliance { kRed, kBlue, kInvalid };
   enum MatchType { kNone, kPractice, kQualification, kElimination };
diff --git a/wpilibc/src/main/native/include/frc/livewindow/LiveWindow.h b/wpilibc/src/main/native/include/frc/livewindow/LiveWindow.h
index 6851cde897..29e4f47cdb 100644
--- a/wpilibc/src/main/native/include/frc/livewindow/LiveWindow.h
+++ b/wpilibc/src/main/native/include/frc/livewindow/LiveWindow.h
@@ -18,7 +18,7 @@ namespace frc {
  * The LiveWindow class is the public interface for putting sensors and
  * actuators on the LiveWindow.
  */
-class LiveWindow {
+class LiveWindow final {
  public:
   /**
    * Get an instance of the LiveWindow main class.
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/DriverStation.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/DriverStation.java
index 2c10187143..5971a0fffd 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/DriverStation.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/DriverStation.java
@@ -24,7 +24,7 @@ import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
 /** Provide access to the network communication data to / from the Driver Station. */
-public class DriverStation {
+public final class DriverStation {
   /** Number of Joystick Ports. */
   public static final int kJoystickPorts = 6;
 
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/counter/UpDownCounter.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/counter/UpDownCounter.java
index 81d504e032..491e9222b3 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/counter/UpDownCounter.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/counter/UpDownCounter.java
@@ -21,8 +21,8 @@ import java.nio.ByteOrder;
  * digital input and down on an edge from another digital input.
  */
 public class UpDownCounter implements Sendable, AutoCloseable {
-  private DigitalSource m_upSource;
-  private DigitalSource m_downSource;
+  private final DigitalSource m_upSource;
+  private final DigitalSource m_downSource;
 
   private final int m_handle;
 
@@ -43,6 +43,8 @@ public class UpDownCounter implements Sendable, AutoCloseable {
       CounterJNI.setCounterUpSource(
           m_handle, upSource.getPortHandleForRouting(), upSource.getAnalogTriggerTypeForRouting());
       CounterJNI.setCounterUpSourceEdge(m_handle, true, false);
+    } else {
+      m_upSource = null;
     }
 
     if (downSource != null) {
@@ -52,6 +54,8 @@ public class UpDownCounter implements Sendable, AutoCloseable {
           downSource.getPortHandleForRouting(),
           downSource.getAnalogTriggerTypeForRouting());
       CounterJNI.setCounterDownSourceEdge(m_handle, true, false);
+    } else {
+      m_downSource = null;
     }
 
     reset();
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/livewindow/LiveWindow.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/livewindow/LiveWindow.java
index ff3e8ef5fe..cb4ae26602 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/livewindow/LiveWindow.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/livewindow/LiveWindow.java
@@ -14,7 +14,7 @@ import edu.wpi.first.wpilibj.smartdashboard.SendableBuilderImpl;
 /**
  * The LiveWindow class is the public interface for putting sensors and actuators on the LiveWindow.
  */
-public class LiveWindow {
+public final class LiveWindow {
   private static class Component {
     boolean m_firstTime = true;
     boolean m_telemetryEnabled = true;
diff --git a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/sensors/RomiGyro.java b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/sensors/RomiGyro.java
index c21f62317e..a0ee53d542 100644
--- a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/sensors/RomiGyro.java
+++ b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/sensors/RomiGyro.java
@@ -9,12 +9,12 @@ import edu.wpi.first.hal.SimDevice.Direction;
 import edu.wpi.first.hal.SimDouble;
 
 public class RomiGyro {
-  private SimDouble m_simRateX;
-  private SimDouble m_simRateY;
-  private SimDouble m_simRateZ;
-  private SimDouble m_simAngleX;
-  private SimDouble m_simAngleY;
-  private SimDouble m_simAngleZ;
+  private final SimDouble m_simRateX;
+  private final SimDouble m_simRateY;
+  private final SimDouble m_simRateZ;
+  private final SimDouble m_simAngleX;
+  private final SimDouble m_simAngleY;
+  private final SimDouble m_simAngleZ;
 
   private double m_angleXOffset;
   private double m_angleYOffset;
@@ -32,6 +32,14 @@ public class RomiGyro {
       m_simAngleX = gyroSimDevice.createDouble("angle_x", Direction.kInput, 0.0);
       m_simAngleY = gyroSimDevice.createDouble("angle_y", Direction.kInput, 0.0);
       m_simAngleZ = gyroSimDevice.createDouble("angle_z", Direction.kInput, 0.0);
+    } else {
+      m_simRateX = null;
+      m_simRateY = null;
+      m_simRateZ = null;
+
+      m_simAngleX = null;
+      m_simAngleY = null;
+      m_simAngleZ = null;
     }
   }
 
diff --git a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/subsystems/OnBoardIO.java b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/subsystems/OnBoardIO.java
index 848aff54f3..0199f6a8ba 100644
--- a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/subsystems/OnBoardIO.java
+++ b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/romireference/subsystems/OnBoardIO.java
@@ -22,12 +22,12 @@ public class OnBoardIO extends SubsystemBase {
   private final DigitalOutput m_yellowLed = new DigitalOutput(3);
 
   // DIO 1
-  private DigitalInput m_buttonB;
-  private DigitalOutput m_greenLed;
+  private final DigitalInput m_buttonB;
+  private final DigitalOutput m_greenLed;
 
   // DIO 2
-  private DigitalInput m_buttonC;
-  private DigitalOutput m_redLed;
+  private final DigitalInput m_buttonC;
+  private final DigitalOutput m_redLed;
 
   private static final double MESSAGE_INTERVAL = 1.0;
   private double m_nextMessageTime;
@@ -46,13 +46,17 @@ public class OnBoardIO extends SubsystemBase {
   public OnBoardIO(ChannelMode dio1, ChannelMode dio2) {
     if (dio1 == ChannelMode.INPUT) {
       m_buttonB = new DigitalInput(1);
+      m_greenLed = null;
     } else {
+      m_buttonB = null;
       m_greenLed = new DigitalOutput(1);
     }
 
     if (dio2 == ChannelMode.INPUT) {
       m_buttonC = new DigitalInput(2);
+      m_redLed = null;
     } else {
+      m_buttonC = null;
       m_redLed = new DigitalOutput(2);
     }
   }
diff --git a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/statespacedifferentialdrivesimulation/subsystems/DriveSubsystem.java b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/statespacedifferentialdrivesimulation/subsystems/DriveSubsystem.java
index e9742696d4..15181405db 100644
--- a/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/statespacedifferentialdrivesimulation/subsystems/DriveSubsystem.java
+++ b/wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/statespacedifferentialdrivesimulation/subsystems/DriveSubsystem.java
@@ -62,11 +62,11 @@ public class DriveSubsystem extends SubsystemBase {
 
   // These classes help us simulate our drivetrain
   public DifferentialDrivetrainSim m_drivetrainSimulator;
-  private EncoderSim m_leftEncoderSim;
-  private EncoderSim m_rightEncoderSim;
+  private final EncoderSim m_leftEncoderSim;
+  private final EncoderSim m_rightEncoderSim;
   // The Field2d class shows the field in the sim GUI
-  private Field2d m_fieldSim;
-  private ADXRS450_GyroSim m_gyroSim;
+  private final Field2d m_fieldSim;
+  private final ADXRS450_GyroSim m_gyroSim;
 
   /** Creates a new DriveSubsystem. */
   public DriveSubsystem() {
@@ -101,6 +101,12 @@ public class DriveSubsystem extends SubsystemBase {
       // the Field2d class lets us visualize our robot in the simulation GUI.
       m_fieldSim = new Field2d();
       SmartDashboard.putData("Field", m_fieldSim);
+    } else {
+      m_leftEncoderSim = null;
+      m_rightEncoderSim = null;
+      m_gyroSim = null;
+
+      m_fieldSim = null;
     }
   }
 
diff --git a/wpimath/src/main/java/edu/wpi/first/math/interpolation/TimeInterpolatableBuffer.java b/wpimath/src/main/java/edu/wpi/first/math/interpolation/TimeInterpolatableBuffer.java
index 676bd7c7f7..7672b368c0 100644
--- a/wpimath/src/main/java/edu/wpi/first/math/interpolation/TimeInterpolatableBuffer.java
+++ b/wpimath/src/main/java/edu/wpi/first/math/interpolation/TimeInterpolatableBuffer.java
@@ -16,7 +16,7 @@ import java.util.TreeMap;
  *
  * @param <T> The type stored in this buffer.
  */
-public class TimeInterpolatableBuffer<T> {
+public final class TimeInterpolatableBuffer<T> {
   private final double m_historySize;
   private final InterpolateFunction<T> m_interpolatingFunc;
   private final NavigableMap<Double, T> m_buffer = new TreeMap<>();
diff --git a/wpiutil/src/main/java/edu/wpi/first/util/sendable/SendableRegistry.java b/wpiutil/src/main/java/edu/wpi/first/util/sendable/SendableRegistry.java
index 2a4c2c9bdb..88e8ec5e98 100644
--- a/wpiutil/src/main/java/edu/wpi/first/util/sendable/SendableRegistry.java
+++ b/wpiutil/src/main/java/edu/wpi/first/util/sendable/SendableRegistry.java
@@ -17,7 +17,7 @@ import java.util.function.Supplier;
  * The SendableRegistry class is the public interface for registering sensors and actuators for use
  * on dashboards and LiveWindow.
  */
-public class SendableRegistry {
+public final class SendableRegistry {
   private static class Component {
     Component() {}
 
diff --git a/wpiutil/src/main/native/include/wpi/sendable/SendableRegistry.h b/wpiutil/src/main/native/include/wpi/sendable/SendableRegistry.h
index a08f9e9eeb..463974930b 100644
--- a/wpiutil/src/main/native/include/wpi/sendable/SendableRegistry.h
+++ b/wpiutil/src/main/native/include/wpi/sendable/SendableRegistry.h
@@ -20,7 +20,7 @@ class SendableBuilder;
  * The SendableRegistry class is the public interface for registering sensors
  * and actuators for use on dashboards and LiveWindow.
  */
-class SendableRegistry {
+class SendableRegistry final {
  public:
   SendableRegistry() = delete;