#12 -- Fix NPE

src/main/java/ru/ulstu/extractor/model/Commit.java

@@ -91,6 +91,10 @@ public class Commit extends BaseEntity {
     }
 
     public boolean containsEntity() {
-        return fileChanges.stream().anyMatch(FileChange::isContainsEntity);
+        return fileChanges != null && fileChanges.stream().anyMatch(
+                fileChange -> fileChange != null
+                        && fileChange.isContainsEntity() != null
+                        && fileChange.isContainsEntity()
+        );
     }
 }

src/main/java/ru/ulstu/extractor/model/FileChange.java

@@ -25,7 +25,7 @@ public class FileChange extends BaseEntity {
     @Transient
     private boolean added;
 
-    private boolean containsEntity;
+    private Boolean containsEntity;
 
     @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
     @JoinColumn(name = "file_change_id", unique = true)
@@ -79,7 +79,7 @@ public class FileChange extends BaseEntity {
         return added;
     }
 
-    public boolean isContainsEntity() {
+    public Boolean isContainsEntity() {
         return containsEntity;
     }