@Override
    public T[] copyStackFrame() {
        // without synchronization arraycopy, last index is null reference
        final T[] currentStack = this.stack;
        final T[] copyStack = newStack(factory.getType(), currentStack.length);
        System.arraycopy(currentStack, 0, copyStack, 0, currentStack.length);
        return copyStack;
    }
@author netspider
@author Woonduk Kang(emeroad)
@author jaehong.kim
agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/context/DefaultCallStack.java