NullPointerException in UnrarHeadertype

[cxMax]

• situation : when decompress .rar file in andorid . I determine whether the .rar file is valid. I use the below codes.

public boolean isValid() {
        return mArchive != null && mArchive.getMainHeader() != null;
}

• problem : unfortunately, mArchive.getMainHeader() return null. because there is a NullPoniterException Occured in Archive.java line.248/251.

in UnrarHeadertype.java , when headerType = 3 ; UnrarHeadertype.findType(3) returns null; i'm confused about how to resolve it , can you help me ? thx a lot.