string search using OQL

Question

I am using VisualVM to analyze a core dump. I suspect some XML objects to be causing the leak but there are way too many String objects to go through one by one.

Can I use OQL to search String that begin with 'GH' ?

thanks for any help.

Valenzuela

Answer 1

Try this: select {instance: s, content: s.toString()} from java.lang.String s where s.count>2 && s.toString().substring(0,2)=="GH"

Donaghue

Answer 2

under JDK 1.8.20 a more simple variant works:

select s from java.lang.String s where s.toString().startsWith("GH")

Qp

Thank you for this. Where do you find documentation for all the supported methods? Googling only leads to random blogs that don't work – Dulles

just looked at the answer below and guessed that startsWith could work. also as I heard it's possible to use sql with a heap dump – Qp

Answer 3

heap.objects('java.lang.String', false, "it.toString().startsWith('GH')")

Reld

A short ummary would help reviewers (like me) to judge the validity of your answer; interested users wouldn't have to dive into the code to understand your appoach. Just a sentence or two would be fine and not too much work. – Giffard

Answer 4

select c.attr_name.toString() from a.b.c.MyClass c where c.attr_name.toString().startsWith("GH")

Lynnet