Sun Performance and Tuning: Java™ and the Internet, Second Edition

Cache Principles

Caches work on two basic principles that should be quite familiar to you from everyday life. The first is that if you spend a long time going to get something and you think you may need it again soon, you keep it nearby. For example, if you are working on your car, you find a 15 mm spanner in your tool box, then crawl under the car. If you then need a 10 mm spanner, you don’t put the 15 mm back in the tool box, you leave it under the car. When you have finished, there is a cache of tools in a pile under the car that make up your working set. If you allowed only one tool at a time under the car, you would waste a lot of time going back to the tool box. However, if the pile of tools gets too large, you may decide to put away a ...