fixes for Javadoc errors and some warnings (#95)

johnzon-core/src/main/java/org/apache/johnzon/core/BufferStrategyFactory.java

@@ -51,6 +51,8 @@ private BufferStrategyFactory() {
      *
      * You can also pass in a fully qualified class name of a custom {@link BufferStrategy}.
      *
+     * @param strategyName one of the supported BufferStrategies as per above
+     * @return an instance of the chosen BufferStrategy
      * @throws IllegalArgumentException if the given strategyName does not resolve to a BufferStrategy.
      */
     public static BufferStrategy valueOf(String strategyName) {

johnzon-core/src/main/java/org/apache/johnzon/core/Buffered.java

@@ -17,7 +17,7 @@
 package org.apache.johnzon.core;
 
 /**
- * A <tt>Buffered</tt> is a source or destination of data that is buffered
+ * A <code>Buffered</code> is a source or destination of data that is buffered
  * before writing or reading.  The bufferSize method allows all participants
  * in the underlying stream to align on this buffer size for optimization.
  *
@@ -31,6 +31,7 @@ public interface Buffered { // https://github.com/apache/johnzon/pull/84#discuss
     /**
      * The buffer size used by this stream while reading input or before writing
      * output to the underlying stream.
+     * @return the size of the buffer
      */
     int bufferSize();
 }

johnzon-core/src/main/java/org/apache/johnzon/core/JsonStreamParserImpl.java

@@ -208,6 +208,7 @@ private void doAutoAdjust(final int length) {
     }
 
     /**
+     * @param currentLength length of the buffer
      * @return the amount of bytes the current buffer should get extended with
      */
     protected int getBufferExtends(int currentLength) {

johnzon-core/src/main/java/org/apache/johnzon/core/util/ArrayUtil.java

@@ -146,6 +146,8 @@ public int size() {
 
     /**
      * Take the given array object and fill a fresh Collection with it.
+     * @param array an array that is to be duplicated
+     * @return a new collection of the original array elements
      * @throws IllegalArgumentException if the given value this is not an array.
      */
     public static Collection<Object> newCollection(Object array) {

johnzon-mapper/src/main/java/org/apache/johnzon/mapper/Adapter.java

@@ -22,13 +22,14 @@
  * An Adapter is similar to a {@link Converter}.
  * The main difference is that a Converter always converts from/to a String.
  * An adapter might e.g. convert to a Date or any other Object which will
- * then be json-ified.<p>
+ * then be json-ified.
  *
  * A small example which has a special Java type to internally represent dates.
  * Let's call it {@code DateHolder}.
  * Our {@code Mapper} should treat it as a {@code java.util.Date}.
  * For doing so we create a {@code DateHolderAdapter} like the following example shows:
  * <pre>
+ * {@code
  * public static class DateHolderAdapter implements Adapter<DateHolder, Date> {
  *     @Override
  *     public DateHolder to(Date date) {
@@ -41,6 +42,7 @@
  *        return new Date(dateHolder.getDate());
  *     }
  * }
+ * }
  * </pre>
  *
  * Consider a POJO has a DateHolder.
@@ -53,11 +55,15 @@
 public interface Adapter<POJO_TYPE, JSON_TYPE> extends MapperConverter {
     /**
      * Transfer JSONTYPE_TYPE from JSON to POJO as POJO_TYPE.
+     * @param b the JSON type
+     * @return the equivalent Java type
      */
     POJO_TYPE to(JSON_TYPE b);
 
     /**
      * Take the POJO_TYPE object A from a POJO an convert it to JSON_TYPE which will be inserted into the JSON output.
+     * @param a the Java type
+     * @return the equivalent JSON type
      */
     JSON_TYPE from(POJO_TYPE a);
 }

johnzon-mapper/src/main/java/org/apache/johnzon/mapper/Converter.java

@@ -26,13 +26,13 @@
  *
  * An example would be to convert joda LocalDate into Strings and back.
  *
- * @param <T>
+ * @param <T> the Java type that needs to be converted
  */
 public interface Converter<T> extends MapperConverter {
     String toString(T instance);
     T fromString(String text);
 
-    // for generic converters it allows to explicitely provide the converted type (ex: enum converter)
+    // for generic converters it allows to explicitly provide the converted type (ex: enum converter)
     // typically useful when generic type get resolved to a TypeVariable
     interface TypeAccess {
         Type type();

johnzon-mapper/src/main/java/org/apache/johnzon/mapper/JohnzonDeduplicateObjects.java

@@ -30,7 +30,7 @@
  * The feature only gets activated if this annotation is available
  * on the root object to be serialised/deserialised.
  *
- * @see MapperBuilder#setDeduplicateObjects(boolean)
+ * @see MapperBuilder#setDeduplicateObjects(Boolean)
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.TYPE})