------------------------ Objects | ------------------------ # JDK7µÄй¤¾ßÀà,¶¼ÊǾ²Ì¬·½·¨ ------------------------ ¾²Ì¬·½·¨ | ------------------------ boolean isNull(Object obj); # Åж϶ÔÏóÊÇ·ñΪ¿Õ boolean nonNull(Object obj); # Åж϶ÔÏóÊÇ·ñΪ¿Õ