The >> operator is the bitwise right shift operator.
Simple example:
int i = 4;
System.out.println(i >> 1); // prints 2 - since shift right is equal to divide by 2
System.out.println(i << 1); // prints 8 - since shift left is equal to multiply by 2
Negative numbers behave the same:
int i = -4;
System.out.println(i >> 1); // prints -2
System.out.println(i << 1); // prints -8
Generally speaking – i << k is equivalent to i*(2^k), while i >> k is equivalent to i/(2^k).
In all cases (just as with any other arithmetic operator), you should always make sure you do not overflow your data type.