package com.zaliczenie.projekt;

import java.io.File;

public interface IDuplicateChecker {
    boolean checkIfItemsAreDuplicates(File file1, File file2);
}

package com.zaliczenie.projekt;a

import java.io.File;

public interface IDuplicateChecker {
    boolean checkIfItemsAreDuplicates(File file1, File file2);
}

Update IDuplicateChecker.java