Question

Using the Eclipse profiler, I am interested in number of allocated instances of classes from java.lang (for instance String). I also want to know stuff like number of calls to String.equals() etc.

I use the “Object Allocations” tab and I shows all classes in my application and a count, but there is no mention of any standard java classes.

For instance, this silly code shows up in the Object Allocations tab as 1000 Foo, 7 byte[], 4 char[] and 2 int[]. Nothing else.

public static void main(String[] args) 
{
    Object obj[] = new Object[1000];
    for (int i = 0; i < 1000; i++) {
        new Foo();  // Some custom class
        obj[i] = new StringBuffer("foo" + i);
    }
    System.out.println (obj[30]);
}

It seems the profiler simply ignores everything that is in any of the java.* packages. The same applies to Execution Statistics as well.

Do I need to enable instrumentation for the core java classes or is there some setting I am missing here?

Answer 1

If you’re using the same Eclipse profiler listed here you need to set the inclusion/exclusion filters up. In your case, you can add a particular package or class to the inclusion filter, or simply remove it from the exclusion filter pre-defined. I would go with the former as its the more conservative approach and will most likely have a lower impact on your application performance. Removing something from the exclusion filter may result it removing more than you intended or wanted, meaning that more code is instrumented.