Nullable: Switch to TYPE_USE

Since JGit now requires Java 8, we can switch to TYPE_USE instead
of explicitly specifying the target type.

Some of the existing uses of Nullable need to be reworked slightly
as described in [1] to prevent the compilation error:

  scoping construct cannot be annotated with type-use annotation

[1] https://stackoverflow.com/a/21385939/381622

Change-Id: Idba48f67a09353b5237685996ce828c8ca398168
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/LargeFileRepository.java

@@ -82,7 +82,7 @@ public interface LargeFileRepository {
 	 * @return Action for verifying the object, or {@code null} if the server
 	 *         doesn't support or require verification
 	 */
-	public @Nullable Response.Action getVerifyAction(AnyLongObjectId id);
+	public Response.@Nullable Action getVerifyAction(AnyLongObjectId id);
 
 	/**
 	 * Get size of an object

org.eclipse.jgit/src/org/eclipse/jgit/annotations/Nullable.java

@@ -43,12 +43,8 @@
 
 package org.eclipse.jgit.annotations;
 
-import static java.lang.annotation.ElementType.FIELD;
-import static java.lang.annotation.ElementType.LOCAL_VARIABLE;
-import static java.lang.annotation.ElementType.METHOD;
-import static java.lang.annotation.ElementType.PARAMETER;
-
 import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -93,7 +89,7 @@ import java.lang.annotation.Target;
  */
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
-@Target({ FIELD, METHOD, PARAMETER, LOCAL_VARIABLE })
+@Target(ElementType.TYPE_USE)
 public @interface Nullable {
 	// marker annotation with no members
 }

org.eclipse.jgit/src/org/eclipse/jgit/errors/CorruptObjectException.java

@@ -140,8 +140,7 @@ public class CorruptObjectException extends IOException {
 	 * @return error condition or null.
 	 * @since 4.2
 	 */
-	@Nullable
-	public ObjectChecker.ErrorType getErrorType() {
+	public ObjectChecker.@Nullable ErrorType getErrorType() {
 		return errorType;
 	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/internal/fsck/FsckError.java

@@ -89,8 +89,7 @@ public class FsckError {
 		}
 
 		/** @return error type of the corruption. */
-		@Nullable
-		public ObjectChecker.ErrorType getErrorType() {
+		public ObjectChecker.@Nullable ErrorType getErrorType() {
 			return errorType;
 		}
 	}

org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java

@@ -265,8 +265,7 @@ public class TransferConfig {
 			}
 		}
 
-		@Nullable
-		static ObjectChecker.ErrorType parse(String key) {
+		static ObjectChecker.@Nullable ErrorType parse(String key) {
 			return errors.get(toLowerCase(key));
 		}