[docs] Add missing JavaDocs (#6125)

wpiutil/src/main/java/edu/wpi/first/util/CircularBuffer.java

@@ -4,7 +4,11 @@
 
 package edu.wpi.first.util;
 
-/** This is a simple circular buffer so we don't need to "bucket brigade" copy old values. */
+/**
+ * This is a simple circular buffer so we don't need to "bucket brigade" copy old values.
+ *
+ * @param <T> Buffer element type.
+ */
 public class CircularBuffer<T> {
   private T[] m_data;
 
@@ -17,7 +21,7 @@ public class CircularBuffer<T> {
   /**
    * Create a CircularBuffer with the provided size.
    *
-   * @param size The size of the circular buffer.
+   * @param size Maximum number of buffer elements.
    */
   @SuppressWarnings("unchecked")
   public CircularBuffer(int size) {

wpiutil/src/main/java/edu/wpi/first/util/InterpolatingTreeMap.java

@@ -10,6 +10,8 @@ import java.util.TreeMap;
  * Interpolating Tree Maps are used to get values at points that are not defined by making a guess
  * from points that are defined. This uses linear interpolation.
  *
+ * @param <K> Key type.
+ * @param <V> Value type.
  * @deprecated Use {@link edu.wpi.first.math.interpolation.InterpolatingDoubleTreeMap} instead
  */
 @Deprecated(forRemoval = true, since = "2024")

wpiutil/src/main/java/edu/wpi/first/util/WPIUtilJNI.java

@@ -8,20 +8,35 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+/** WPIUtil JNI. */
 public class WPIUtilJNI {
   static boolean libraryLoaded = false;
   static RuntimeLoader<WPIUtilJNI> loader = null;
 
+  /** Sets whether JNI should be loaded in the static block. */
   public static class Helper {
     private static AtomicBoolean extractOnStaticLoad = new AtomicBoolean(true);
 
+    /**
+     * Returns true if the JNI should be loaded in the static block.
+     *
+     * @return True if the JNI should be loaded in the static block.
+     */
     public static boolean getExtractOnStaticLoad() {
       return extractOnStaticLoad.get();
     }
 
+    /**
+     * Sets whether the JNI should be loaded in the static block.
+     *
+     * @param load Whether the JNI should be loaded in the static block.
+     */
     public static void setExtractOnStaticLoad(boolean load) {
       extractOnStaticLoad.set(load);
     }
+
+    /** Utility class. */
+    private Helper() {}
   }
 
   static {
@@ -137,4 +152,7 @@ public class WPIUtilJNI {
    */
   public static native int[] waitForObjectsTimeout(int[] handles, double timeout)
       throws InterruptedException;
+
+  /** Utility class. */
+  protected WPIUtilJNI() {}
 }

wpiutil/src/main/java/edu/wpi/first/util/struct/BadSchemaException.java

@@ -5,6 +5,7 @@
 package edu.wpi.first.util.struct;
 
 public class BadSchemaException extends Exception {
+  /** The bad schema field. */
   private final String m_field;
 
   public BadSchemaException(String s) {

wpiutil/src/main/java/edu/wpi/first/util/struct/parser/ParseException.java

@@ -5,6 +5,7 @@
 package edu.wpi.first.util.struct.parser;
 
 public class ParseException extends Exception {
+  /** The parser position. */
   private final int m_pos;
 
   public ParseException(int pos, String s) {