Clean-up

src/main/java/at/pcgamingfreaks/mkvaudiosubtitlechanger/config/Config.java

@@ -69,6 +69,10 @@ public class Config {
                     mkvToolNix.getAbsolutePath() + "/" + application;
     }
 
+    public String getNormalizedLibraryPath() {
+        return this.getLibraryPath().getAbsolutePath().replace("\\", "/");
+    }
+
     @Override
     public String toString() {
         return new StringJoiner(", ", Config.class.getSimpleName() + "[", "]")

src/main/java/at/pcgamingfreaks/mkvaudiosubtitlechanger/config/validator/ConfigValidator.java

@@ -100,10 +100,16 @@ public abstract class ConfigValidator<FieldType> {
         };
     }
 
+    /**
+     * @return true if overwriting this property is necessary.
+     */
     protected boolean isOverwritingNecessary() {
         return false;
     }
 
+    /**
+     * @return {@link FieldType} to overwrite result with.
+     */
     protected FieldType overwriteValue() {
         return null;
     }

src/main/java/at/pcgamingfreaks/mkvaudiosubtitlechanger/config/validator/DateValidator.java

@@ -37,7 +37,7 @@ public class DateValidator extends ConfigValidator<Date> {
                 return DEFAULT_DATE;
             }
             YAML yaml = new YAML(lastExecutionFile);
-            return parse(yaml.getString(Config.getInstance().getLibraryPath().getAbsolutePath().replace("\\", "/"), DateUtils.convert(DEFAULT_DATE)));
+            return parse(yaml.getString(Config.getInstance().getNormalizedLibraryPath(), DateUtils.convert(DEFAULT_DATE)));
         } catch (YamlInvalidContentException | IOException e) {
             log.error("Couldn't open last-execution.properties");
             return INVALID_DATE;