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Can you please explain this code snippet from HashMap constructor specifically the line
capacity <<= 1:
// Find a power of 2 >= initialCapacity
198 int capacity = 1;
199 while (capacity < initialCapacity)
200 capacity <<= 1;
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"<<" means left shift the bits of a value. ">>" means right shift the bits of a value. example: int a = 5; //the binary value of 5 is 101.
What Does Operator Mean? An operator, in Java, is a special symbols performing specific operations on one, two or three operands and then returning a result. The operators are classified and listed according to precedence order. Java operators are generally used to manipulate primitive data types.
The signed left shift operator << shifts a bit pattern to the left, and the signed right shift operator >> shifts a bit pattern to the right. The bit pattern is given by the left-hand operand, and the number of positions to shift by the right-hand operand.
The >>> operator is the unsigned right bit-shift operator in Java. It effectively divides the operand by 2 to the power of the right operand, or just 2 here.
It is equivalent to capacity = capacity << 1;.
That operation shifts capacity's bits one position to the left, which is equivalent to multiplying by 2.
The specific code you posted finds the smallest power of 2 which is larger than initialCapacity.
So if initialCapacity is 27, for example, capacity will be 32 (2^5) after the loop.
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