@Nullable
    public JpegComponent getComponent(int componentNumber)
    {
        int tagType = JpegDirectory.TAG_COMPONENT_DATA_1 + componentNumber;
        return (JpegComponent)getObject(tagType);
    }
@ Nullable public JpegComponent getComponent ( int componentNumber ) { int tagType = JpegDirectory . TAG_COMPONENT_DATA_1 + componentNumber ; return ( JpegComponent ) getObject ( tagType ) ; }
@param componentNumber The zero-based index of the component.  This number is normally between 0 and 3.
Use getNumberOfComponents for bounds-checking.
@return the JpegComponent having the specified number.