Disable frivolous PMD warnings and enable PMD in ntcore (#3419)

Some valid warnings like throwing NullPointerException or using a for
loop instead of System.arraycopy() were fixed.

Abstract classes marked with PMD.AbstractClassWithoutAbstractMethod were
made concrete because they already had protected constructors.

Fixes #1697.

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandBase.java

@@ -11,7 +11,6 @@ import java.util.HashSet;
 import java.util.Set;
 
 /** A {@link Sendable} base class for {@link Command}s. */
-@SuppressWarnings("PMD.AbstractClassWithoutAbstractMethod")
 public abstract class CommandBase implements Sendable, Command {
 
   protected Set<Subsystem> m_requirements = new HashSet<>();

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/CommandScheduler.java

@@ -34,7 +34,6 @@ import java.util.function.Consumer;
  * CommandScheduler#registerSubsystem(Subsystem...)} in order for their {@link Subsystem#periodic()}
  * methods to be called and for their default commands to be scheduled.
  */
-@SuppressWarnings({"PMD.GodClass", "PMD.TooManyFields"})
 public final class CommandScheduler implements Sendable, AutoCloseable {
   /** The Singleton Instance. */
   private static CommandScheduler instance;
@@ -157,7 +156,6 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
    * @param interruptible whether this command can be interrupted
    * @param command the command to schedule
    */
-  @SuppressWarnings({"PMD.CyclomaticComplexity", "PMD.NPathComplexity"})
   private void schedule(boolean interruptible, Command command) {
     if (m_inRunLoop) {
       m_toSchedule.put(command, interruptible);
@@ -239,7 +237,6 @@ public final class CommandScheduler implements Sendable, AutoCloseable {
    *
    * <p>Any subsystems not being used as requirements have their default methods started.
    */
-  @SuppressWarnings({"PMD.CyclomaticComplexity", "PMD.NPathComplexity"})
   public void run() {
     if (m_disabled) {
       return;

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/MecanumControllerCommand.java

@@ -36,7 +36,7 @@ import java.util.function.Supplier;
  * <p>The robot angle controller does not follow the angle given by the trajectory but rather goes
  * to the angle given in the final state of the trajectory.
  */
-@SuppressWarnings({"PMD.TooManyFields", "MemberName"})
+@SuppressWarnings("MemberName")
 public class MecanumControllerCommand extends CommandBase {
   private final Timer m_timer = new Timer();
   private final boolean m_usePID;
@@ -85,7 +85,7 @@ public class MecanumControllerCommand extends CommandBase {
    *     voltages.
    * @param requirements The subsystems to require.
    */
-  @SuppressWarnings({"PMD.ExcessiveParameterList", "ParameterName"})
+  @SuppressWarnings("ParameterName")
   public MecanumControllerCommand(
       Trajectory trajectory,
       Supplier<Pose2d> pose,
@@ -177,7 +177,7 @@ public class MecanumControllerCommand extends CommandBase {
    *     voltages.
    * @param requirements The subsystems to require.
    */
-  @SuppressWarnings({"PMD.ExcessiveParameterList", "ParameterName"})
+  @SuppressWarnings("ParameterName")
   public MecanumControllerCommand(
       Trajectory trajectory,
       Supplier<Pose2d> pose,
@@ -235,7 +235,7 @@ public class MecanumControllerCommand extends CommandBase {
    * @param outputWheelSpeeds A MecanumDriveWheelSpeeds object containing the output wheel speeds.
    * @param requirements The subsystems to require.
    */
-  @SuppressWarnings({"PMD.ExcessiveParameterList", "ParameterName"})
+  @SuppressWarnings("ParameterName")
   public MecanumControllerCommand(
       Trajectory trajectory,
       Supplier<Pose2d> pose,
@@ -307,7 +307,7 @@ public class MecanumControllerCommand extends CommandBase {
    * @param outputWheelSpeeds A MecanumDriveWheelSpeeds object containing the output wheel speeds.
    * @param requirements The subsystems to require.
    */
-  @SuppressWarnings({"PMD.ExcessiveParameterList", "ParameterName"})
+  @SuppressWarnings("ParameterName")
   public MecanumControllerCommand(
       Trajectory trajectory,
       Supplier<Pose2d> pose,

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/RamseteCommand.java

@@ -30,7 +30,6 @@ import java.util.function.Supplier;
  * functionality of a "smart" motor controller) may use the secondary constructor that omits the PID
  * and feedforward functionality, returning only the raw wheel speeds from the RAMSETE controller.
  */
-@SuppressWarnings("PMD.TooManyFields")
 public class RamseteCommand extends CommandBase {
   private final Timer m_timer = new Timer();
   private final boolean m_usePID;
@@ -68,7 +67,6 @@ public class RamseteCommand extends CommandBase {
    *     the robot drive.
    * @param requirements The subsystems to require.
    */
-  @SuppressWarnings("PMD.ExcessiveParameterList")
   public RamseteCommand(
       Trajectory trajectory,
       Supplier<Pose2d> pose,