Add missing javadoc for archive code

Document archive formats, the archive format interface, and the
parameters of the GitAPIException constructors.  Noticed by eclipse.

Reported-by: Dani Megert <Daniel_Megert@ch.ibm.com>
Change-Id: I22b5f9d4c0358bbe867c1906feec7c279e214273

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/FormatActivator.java

  * leaks).
  */
 public class FormatActivator implements BundleActivator {
+	/**
+	 * Registers all included archive formats by calling
+	 * {@link #start()}.  This method is called by the OSGi framework
+	 * when the bundle is started.
+	 *
+	 * @param context unused
+	 */
 	public void start(BundleContext context) {
 		ArchiveFormats.registerAll();
 	}
 
+	/**
+	 * Cleans up after {@link #start(BundleContext)} by calling
+	 * {@link #stop()}.
+	 *
+	 * @param context unused
+	 */
 	public void stop(BundleContext context) {
 		ArchiveFormats.unregisterAll();
 	}

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TarFormat.java

 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectLoader;
 
+/**
+ * Unix TAR format (ustar + old GNU long filename extension).
+ */
 public class TarFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	public ArchiveOutputStream createArchiveOutputStream(OutputStream s) {
 		return new TarArchiveOutputStream(s);

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TgzFormat.java

 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectLoader;
 
+/**
+ * gzip-compressed tarball (tar.gz) format.
+ */
 public class TgzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private final ArchiveCommand.Format<ArchiveOutputStream> tarFormat = new TarFormat();
 

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/TxzFormat.java

 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectLoader;
 
+/**
+ * Xz-compressed tar (tar.xz) format.
+ */
 public class TxzFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	private final ArchiveCommand.Format<ArchiveOutputStream> tarFormat = new TarFormat();
 

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/ZipFormat.java

 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectLoader;
 
+/**
+ * PKWARE's ZIP format.
+ */
 public class ZipFormat implements ArchiveCommand.Format<ArchiveOutputStream> {
 	public ArchiveOutputStream createArchiveOutputStream(OutputStream s) {
 		return new ZipArchiveOutputStream(s);

org.eclipse.jgit/src/org/eclipse/jgit/api/ArchiveCommand.java

 	 *	} finally {
 	 *		out.close();
 	 *	}
+	 *
+	 * @param <T>
+	 *            type representing an archive being created.
 	 */
 	public static interface Format<T extends Closeable> {
+		/**
+		 * Start a new archive. Entries can be included in the archive using the
+		 * putEntry method, and then the archive should be closed using its
+		 * close method.
+		 *
+		 * @param s
+		 *            underlying output stream to which to write the archive.
+		 * @return new archive object for use in putEntry
+		 * @throws IOException
+		 *             thrown by the underlying output stream for I/O errors
+		 */
 		T createArchiveOutputStream(OutputStream s) throws IOException;
+
+		/**
+		 * Write an entry to an archive.
+		 *
+		 * @param out
+		 *            archive object from createArchiveOutputStream
+		 * @param path
+		 *            full filename relative to the root of the archive
+		 * @param mode
+		 *            mode (for example FileMode.REGULAR_FILE or
+		 *            FileMode.SYMLINK)
+		 * @param loader
+		 *            blob object with data for this entry
+		 * @throws IOException
+		 *            thrown by the underlying output stream for I/O errors
+		 */
 		void putEntry(T out, String path, FileMode mode,
 				ObjectLoader loader) throws IOException;
 	}

org.eclipse.jgit/src/org/eclipse/jgit/api/errors/GitAPIException.java

 	/**
 	 * Constructs a new exception with the specified detail
 	 * message and cause.
+	 *
+	 * @param message
+	 *            detail message
+	 * @param cause
+	 *            cause
 	 */
 	protected GitAPIException(String message, Throwable cause) {
 		super(message, cause);
 	/**
 	 * Constructs a new exception with the specified detail
 	 * message and no cause.
+	 *
+	 * @param message
+	 *            detail message
 	 */
 	protected GitAPIException(String message) {
 		super(message);