Reason: Improper usage and handling of pointer may lead to memory leakage along with reliability issue.
Apart from this pointer can be used to access the memory area directly and thus could help users with malicious intent in altering sensitive data stored at the memory location in illegal way. This could in turn pose serious security issue. But java is secured language because it does not using pointer.
And most probably this is the reason why java makers decided to omit pointer from java.