android/guava/src/com/google/common/collect/HashBasedTable.java
@Override
  public boolean contains(@NullableDecl Object rowKey, @NullableDecl Object columnKey) {
    return super.contains(rowKey, columnKey);
  }
@Override
  public boolean contains(@NullableDecl Object rowKey, @NullableDecl Object columnKey) {
    return super.contains(rowKey, columnKey);
  }
Overriding so NullPointerTester test passes.