import com.intellij.util.containers.HashSet;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.lang.ref.Reference;
<BUG>import java.util.ArrayList;
import java.util.List;
import java.util.Map;
</BUG>
import java.util.concurrent.ConcurrentMap;

import com.intellij.util.containers.HashSet;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.lang.ref.Reference;
import java.util.*;
import java.util.concurrent.ConcurrentMap;
