Showing posts from April, 2008

MaintainJ Eclipse plug-in


Java metrics

Java career companion

Performance questions

Java Urban Performance Legends

When is it important to set the default collection sizes?What is the time cost of growing an ArrayList?
What is the time cost of growing/rehashing a HashMap with defaults from zero to 'n' entries?initial capacity 16, load factor .75growth algorithm if (size++ >= threshold) resize(2 * table.length)size should always be power of 20-1 million objects ? sec
0-10 million objects ? sec
0-20 million objects - it takes three times the current size to rehash since it doubles the internal array and copies the old array - with a 700M heap couldn't rehash 20 M objects without running out of memory0-20 million objects with 1 GB heap ? sec
Is synchronization expensive?What is the time cost of un-contented synchronization?What is the time cost of contended synchronization?When would pooling of objects yield significant performance gains?How much memory do empty objects require?How much time do objects take to create?How close is …