How important is profiling?

[Mads]

I know that I don't even look at the profiling tools in my IDE. I have no idea how they're relevant to what I'm trying to achieve.
How important is it, and do you keep an eye on it yourself?

I tried looking for a graph on JVM stats, but couldn't find one. Then I gave up.

[sproingie]

Profiling's not at all important til you need it, then it's the best thing evah!

Take a look at VisualVM (your jdk should come with it, called jvisualvm).  That has the sort of graphs you may be looking for, and not just one but two kinds of profiler.   Round it out with a heap profiler (the Eclipse Memory Analyzer Tool, or MAT, is great) and you're cooking with gas.