[vcs-log] add NotNull annotations

platform/vcs-log/api/src/com/intellij/vcs/log/VcsLog.java

@@ -56,6 +56,7 @@ public interface VcsLog {
   /**
    * Selects the commit node defined by the given reference (commit hash, branch or tag).
    */
+  @NotNull
   Future<Boolean> jumpToReference(String reference);
 
   /**

platform/vcs-log/impl/src/com/intellij/vcs/log/impl/VcsLogImpl.java

@@ -85,6 +85,7 @@ public class VcsLogImpl implements VcsLog {
     return myUi.getDataPack().getRefsModel().getAllRefs();
   }
 
+  @NotNull
   @Override
   public Future<Boolean> jumpToReference(final String reference) {
     Collection<VcsRef> references = getAllReferences();

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/VcsLogUiImpl.java

@@ -194,6 +194,7 @@ public class VcsLogUiImpl implements VcsLogUi, Disposable {
     return myUiProperties.isShowRootNames();
   }
 
+  @NotNull
   public Future<Boolean> jumpToCommit(@NotNull Hash commitHash) {
     SettableFuture<Boolean> future = SettableFuture.create();
     jumpTo(commitHash, new PairFunction<GraphTableModel, Hash, Integer>() {
@@ -205,6 +206,7 @@ public class VcsLogUiImpl implements VcsLogUi, Disposable {
     return future;
   }
 
+  @NotNull
   public Future<Boolean> jumpToCommitByPartOfHash(@NotNull String commitHash) {
     SettableFuture<Boolean> future = SettableFuture.create();
     jumpTo(commitHash, new PairFunction<GraphTableModel, String, Integer>() {