Implement AutoClosable interface to support try-with-resources block

Bug: 428039
Change-Id: I41880862db5303b5bea4b2184ba7844d69c997b5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

@@ -82,7 +82,7 @@
  * methods in this class may for example offer too much functionality or they
  * offer the functionality with the wrong arguments.
  */
-public class Git {
+public class Git implements AutoCloseable {
 	/** The git repository this class is interacting with */
 	private final Repository repo;
 

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFile.java

@@ -88,7 +88,7 @@
  * delta packed format yielding high compression of lots of object where some
  * objects are similar.
  */
-public final class DfsPackFile {
+public final class DfsPackFile implements AutoCloseable {
 	/**
 	 * File offset used to cache {@link #index} in {@link DfsBlockCache}.
 	 * <p>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java

@@ -89,7 +89,8 @@
  * delta packed format yielding high compression of lots of object where some
  * objects are similar.
  */
-public class PackFile implements Iterable<PackIndex.MutableEntry> {
+public class PackFile implements Iterable<PackIndex.MutableEntry>,
+		AutoCloseable {
 	/** Sorts PackFiles to be most recently created to least recently created. */
 	public static final Comparator<PackFile> SORT = new Comparator<PackFile>() {
 		public int compare(final PackFile a, final PackFile b) {

org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectDatabase.java

@@ -54,7 +54,7 @@
  * An object database stores one or more Git objects, indexed by their unique
  * {@link ObjectId}.
  */
-public abstract class ObjectDatabase {
+public abstract class ObjectDatabase implements AutoCloseable {
 	/** Initialize a new database instance for access. */
 	protected ObjectDatabase() {
 		// Protected to force extension.

org.eclipse.jgit/src/org/eclipse/jgit/lib/RefDatabase.java

@@ -57,7 +57,7 @@
  * Every {@link Repository} has a single reference database, mapping names to
  * the tips of the object graph contained by the {@link ObjectDatabase}.
  */
-public abstract class RefDatabase {
+public abstract class RefDatabase implements AutoCloseable {
 	/**
 	 * Order of prefixes to search when using non-absolute references.
 	 * <p>

org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

@@ -99,7 +99,7 @@
  * <p>
  * This class is thread-safe.
  */
-public abstract class Repository {
+public abstract class Repository implements AutoCloseable {
 	private static final ListenerList globalListeners = new ListenerList();
 
 	/** @return the global listener list observing all events in this JVM. */