Load factor of Arraylist and Vector?

Question

Hi I was trying to find the load factor of Array list and vector but I was not able to find it. I know load factor of HashMap and other Map is 0.75. Can any one help to find me how to check the load factor of Vector and Arraylist.

Answer 1

ArrayList:

• Initial Capacity:10
• Load Factor:1 (when the list is full)
• Growth Rate: current_size + current_size/2

Vector:

• Initial Capacity:10
• Load Factor:1 (when the list is full)
• Growth Rate: current_size * 2 (if capacityIncrement is not defined) current_size + capacityIncrement (if capacityIncrement is defined during vector initialization)

Answer 2

I assume you would like to know how ArrayList and Vector increase its size.

For ArrayList, every time you put an element into it, it will check if the nested array needs to be enlarge its size. If yes, generally, its size will grow with:

newCapacity = oldCapacity + (oldCapacity >> 1);

For some special case, for example, add many or huge number of elements, things will be different. Please refer grow(int minCapacity) function in java.util.ArrayList source code.

Regarding Vector, generally, its size will grow with:

newCapacity = oldCapacity + ((capacityIncrement > 0) ?
                                         capacityIncrement : oldCapacity);

For some special cases, please refer grow(int minCapacity) in java.util.Vector.