fix

source/src/main/java/one/nem/lacerta/source/file/FileManager.java

@@ -16,7 +16,7 @@ public interface FileManager {
 
     File getFileRef();
     boolean isExist(String name) throws IOException;
-    boolean isExist() throws IOException;
+    boolean isExist();
     boolean isDirectory();
     boolean isFile();
     boolean isWritable();

source/src/main/java/one/nem/lacerta/source/file/impl/FileManagerImpl.java

@@ -77,7 +77,7 @@ public class FileManagerImpl implements FileManager {
     }
 
     @Override
-    public boolean isExist() throws IOException {
+    public boolean isExist(){
         return Files.exists(this.path);
     }