Is there any way to find out the number of objects that gets created?

Question

Is there any way to find out the number of objects that gets created? For example, If I need to find the number of objects that gets created for the below piece of code, how can I get it done? Code:

String [][] str = { {new String("A"),new String("B"),new String("C")}, {new String("D"),new String("E")} };

Answer 1

Yes -- you can use a profiler, like Yourkit.

Answer 2

In this case you can just do

int numberOfObjects = 0;
for(String[] s: str)
{
    numberOfObjects += s.length;
}

Edit: nevermind I'm just really bad at everything forever...

Answer 3

Netbeans and Eclipse both have good profilers that will give you this information. This works if you can run your project in one of these IDE's.

Answer 4

Here's a litle batch file (hoping your running windows) which enables you to walk through the heap of any java app running in a JDK vm, using JDK tools.

It dumps the heap using JMAP, and then runs a webserver using JHAT, then you can surf the (offline) heap :)

@echo off
if not [%1%]==[] goto map
cls
echo.
echo Gebruik: map.cmd [pid#]
echo.
echo ( JVM 6+ required. You're using : %JAVA_HOME% )
echo.
echo Which PID would you like to use?
echo.
jps -l
echo.
pause
exit /b

:map
if exist c:\jmap.txt del c:\jmap.txt
jmap -dump:file=c:\jmap.txt %1
echo.
echo about to start the web-server on port 8081
pause
start http://localhost:8081
start jhat -port 8081 c:\jmap.txt -J-mx512m
echo.