[docs] Add missing HAL CAN javadocs (NFC)

docs/build.gradle

@@ -218,7 +218,6 @@ task generateJavaDocs(type: Javadoc) {
     options.addBooleanOption("Xdoclint/package:" +
             // TODO: v Document these, then remove them from the list
             "-edu.wpi.first.hal," +
-            "-edu.wpi.first.hal.can," +
             "-edu.wpi.first.hal.simulation," +
             // TODO: ^ Document these, then remove them from the list
             "-edu.wpi.first.math.proto," +

hal/src/main/java/edu/wpi/first/hal/can/CANInvalidBufferException.java

@@ -11,10 +11,16 @@
 public class CANInvalidBufferException extends RuntimeException {
   private static final long serialVersionUID = -7993785672956997939L;
 
+  /** Constructs a new CANInvalidBufferException with no message. */
   public CANInvalidBufferException() {
     super();
   }
 
+  /**
+   * Constructs a new CANInvalidBufferException with {@code msg} as its detail message.
+   *
+   * @param msg the message
+   */
   public CANInvalidBufferException(String msg) {
     super(msg);
   }

hal/src/main/java/edu/wpi/first/hal/can/CANMessageNotAllowedException.java

@@ -11,6 +11,11 @@
 public class CANMessageNotAllowedException extends RuntimeException {
   private static final long serialVersionUID = -638450112427013494L;
 
+  /**
+   * Constructs a new CANMessageNotAllowedException with {@code msg} as its detail message.
+   *
+   * @param msg the message
+   */
   public CANMessageNotAllowedException(String msg) {
     super(msg);
   }

hal/src/main/java/edu/wpi/first/hal/can/CANMessageNotFoundException.java

@@ -11,10 +11,16 @@
 public class CANMessageNotFoundException extends RuntimeException {
   private static final long serialVersionUID = 8249780881928189975L;
 
+  /** Constructs a new CANMessageNotFoundException with no message. */
   public CANMessageNotFoundException() {
     super();
   }
 
+  /**
+   * Constructs a new CANMessageNotFoundException with {@code msg} as its detail message.
+   *
+   * @param msg the message
+   */
   public CANMessageNotFoundException(String msg) {
     super(msg);
   }

hal/src/main/java/edu/wpi/first/hal/can/CANNotInitializedException.java

@@ -11,10 +11,16 @@
 public class CANNotInitializedException extends RuntimeException {
   private static final long serialVersionUID = -5982895147092686594L;
 
+  /** Constructs a new CANNotInitializedException with no message. */
   public CANNotInitializedException() {
     super();
   }
 
+  /**
+   * Constructs a new CANNotInitializedException with {@code msg} as its detail message.
+   *
+   * @param msg the message
+   */
   public CANNotInitializedException(String msg) {
     super(msg);
   }

hal/src/main/java/edu/wpi/first/hal/can/CANStreamOverflowException.java

@@ -7,6 +7,11 @@
 import edu.wpi.first.hal.CANStreamMessage;
 import java.io.IOException;
 
+/**
+ * Exception indicating that a CAN stream overflowed at some point between reads, therefore some
+ * messages were lost. This exception contains any messages that were successfully read during the
+ * operation that threw the exception.
+ */
 public class CANStreamOverflowException extends IOException {
   /** The messages. */
   private final CANStreamMessage[] m_messages;
@@ -17,8 +22,8 @@ public class CANStreamOverflowException extends IOException {
   /**
    * Constructs a new CANStreamOverflowException.
    *
-   * @param messages The messages
-   * @param messagesRead The length of messages read
+   * @param messages The messages that were read successfully.
+   * @param messagesRead The length of messages read successfully.
    */
   @SuppressWarnings("PMD.ArrayIsStoredDirectly")
   public CANStreamOverflowException(CANStreamMessage[] messages, int messagesRead) {
@@ -27,11 +32,22 @@ public CANStreamOverflowException(CANStreamMessage[] messages, int messagesRead)
     this.m_messagesRead = messagesRead;
   }
 
+  /**
+   * Gets the messages that were successfully read. Use {@link #getMessagesRead()} to determine how
+   * many messages in the returned array are valid.
+   *
+   * @return the messages
+   */
   @SuppressWarnings("PMD.MethodReturnsInternalArray")
   public CANStreamMessage[] getMessages() {
     return m_messages;
   }
 
+  /**
+   * Gets the count of messages that were successfully read.
+   *
+   * @return count of messages
+   */
   public int getMessagesRead() {
     return m_messagesRead;
   }