address review comments

Author: abh1sar

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/wrapper/LibvirtRestoreBackupCommandWrapper.java

@@ -75,8 +75,12 @@ public Answer execute(RestoreBackupCommand command, LibvirtComputingResource ser
                 restoreVolumesOfDestroyedVMs(volumePaths, vmName, backupPath, backupRepoType, backupRepoAddress, mountOptions);
             }
         } catch (CloudRuntimeException e) {
-            logger.error("Failed to restore backup for VM: " + vmName, e);
-            return new BackupAnswer(command, false, e.getMessage());
+            String errorMessage = "Failed to restore backup for VM: " + vmName + ".";
+            if (e.getMessage() != null && !e.getMessage().isEmpty()) {
+                errorMessage += " Details: " + e.getMessage();
+            }
+            logger.error(errorMessage);
+            return new BackupAnswer(command, false, errorMessage);
         }
 
         return new BackupAnswer(command, true, newVolumeId);

server/src/main/java/org/apache/cloudstack/backup/BackupManagerImpl.java

@@ -278,8 +278,8 @@ public boolean deleteBackupOffering(final Long offeringId) {
 
     public static String createVolumeInfoFromVolumes(List<VolumeVO> vmVolumes) {
         List<Backup.VolumeInfo> list = new ArrayList<>();
-        vmVolumes.sort(Comparator.comparing(Volume::getDeviceId));
-        for (Volume vol : vmVolumes) {
+        vmVolumes.sort(Comparator.comparing(VolumeVO::getDeviceId));
+        for (VolumeVO vol : vmVolumes) {
             list.add(new Backup.VolumeInfo(vol.getUuid(), vol.getPath(), vol.getVolumeType(), vol.getSize()));
         }
         return new Gson().toJson(list.toArray(), Backup.VolumeInfo[].class);