Why .equals(null) doesn't work and == null works? [closed]

Why .equals(null) doesn't work and == null works? [closed]

References

Reference NO 1

http://stackoverflow.com/questions/15190905/why-equalsnull-doesnt-work-and-null-works

Reference NO 2

http://stackoverflow.com/questions/14964921/ifa-testcol-is-null-a-testcol-is-not-null-doesnt-work

Reference NO 3

http://stackoverflow.com/questions/271526/avoiding-null-statements-in-java

Reference NO 4

http://stackoverflow.com/questions/2503628/bitmapfactory-decodestream-returning-null-when-options-are-set

Reference NO 5

http://bugs.mysql.com/6307

Reference NO 6

http://forums.esri.com/Thread.asp?c=93&f=986&t=244542

Reference NO 7

http://www.xaprb.com/blog/2007/05/31/why-is-null-doesnt-always-work-in-mysql/

Reference NO 8

#EANF#