Apple

For those of you who don't want to fork out $500 for a profiler or don't want to waste time trying to make trial versions work when they don't work "out of the box", but would like to get snapshots of objects in memory showing class type, and quantity logged periodically to a log file, DrMem (up to java 1.5 compatible) might be worth a look. http://sourceforge.net/projects/simpleprofiler/. Just download, expand and cd into the Mac OS X dir and type "make". Then copy the lib to java extensions and add launch arguments to your Eclpse launch profile sth like this:

-Xrundrmem:file=/tmp/mywoa_drmem.log,maxObjects=100000,maxTime=30

I tried some other free tools, such as jmap (built-in) and jmp, but did not have any success.

DrMem is a simple agent that does a very simple thing and does it reliably and simply. It logs a snapshot of memory every X objects created. So you can set that to 100000 objects or a million objects. the default is 10 milion. It might be useful also for a deployment scenario where you have a slow memory leak. In development, if you set it to a low number, like 10,000, it is logging so much that it slows your app down.

An example of the head of a memory snapshot is sth like this:

Object allocation report from Tue Nov 24 09:29:28 2009

Number of objects: Currently 5290516, total 11700000

Class list follows:

Currently Total Size Class name

1118670 2338521 27184080 java.lang.String

1099143 2544624 57082952 java.lang.Object

227644 380377 31011472 com.mysql.jdbc.Field

217613 363530 9268712 com.webobjects.jdbcadaptor.JDBCColumn

207533 346759 4980792 com.mysql.jdbc.Buffer

207522 395973 3320352 java.lang.StringBuffer

195982 335331 3148800 java.lang.Integer

144082 277954 3457968 com.webobjects.foundation.NSArray

139885 255724 5595400 com.webobjects.foundation.NSMutableArray

129388 207580 9315936 com.webobjects.eocontrol._EOMutableKnownKeyDictionary

123750 234451 2970088 java.lang.ref.WeakReference

79519 170383 4453064 com.webobjects.foundation.NSMutableDictionary

71734 72600 2869360 com.webobjects.foundation.NSTimestamp

63052 75908 2017664 com.webobjects.eoaccess.EOAccessGenericFaultHandler$_EOHandlerWeakRef

60841 102328 973456 java.util.regex.Pattern$Slice

60421 112258 966736 java.util.regex.Pattern$Dollar

60375 101567 966000 java.util.regex.Pattern$Begin

53924 106458 3019744 java.util.regex.Matcher

51772 51890 2485056 com.webobjects.eocontrol._EOCheapCopyMutableArray

50346 84241 805536 java.util.regex.Pattern$Branch

48027 51862 2305296 com.webobjects.eoaccess.EOAccessArrayFaultHandler

42591 51612 1362912 com.webobjects.eocontrol._EOIntegralKeyGlobalID

40967 62951 1638680 com.webobjects.foundation.NSMutableSet

40262 67612 966288 com.webobjects.foundation._NSWeakMutableCollection$_NSWeakMutableCollectionReferenceEnumerator

35508 35508 1420320 com.webobjects.eocontrol._EOWeakReference

30467 55375 731208 java.util.ArrayList

29864 60907 955648 java.sql.Timestamp

27818 27880 1479704 java.util.WeakHashMap$Entry

27469 27469 1098760 com.webobjects.eoaccess.EODatabase$_DatabaseRecord

23386 265470 658056 java.lang.Class

23067 71772 369072 java.lang.Boolean

22496 39471 719872 com.webobjects.foundation._NSCollectionEnumerator

20206 35317 484944 com.webobjects.foundation.NSNotification

20117 33609 3057784 com.mysql.jdbc.ResultSet

19158 33717 459792 com.webobjects.eocontrol.EOKeyValueQualifier

16800 30915 403200 com.webobjects.foundation._NSJavaArrayEnumerator

16728 49148 487840 java.util.HashMap$Entry

16474 35426 527168 com.webobjects.eoaccess.EODatabaseChannel$_EODatabaseChannelFetchResult

15025 24046 601000 com.webobjects.eoaccess.EOAccessFaultHandler

12396 20520 595008 com.webobjects.eocontrol.EOFetchSpecification

11350 18716 707320 java.lang.reflect.Constructor

10604 10650 254496 er.extensions.appserver.ERXApplication$JarChecker$Entry

10600 30458 678400 java.util.regex.Pattern

10208 143492 874648 java.lang.reflect.Method

10170 30908 565040 java.util.regex.Pattern$GroupHead

10115 29071 161840 java.util.regex.Pattern$Start

10066 17324 241584 java.util.AbstractList$Itr

10060 16797 241440 com.mysql.jdbc.DatabaseMetaData

10059 16798 724248 com.webobjects.jdbcadaptor.MySQLPlugIn$MySQLExpression

10059 16797 160944 com.webobjects.jdbcadaptor.JDBCFetchPrivate

10059 16794 2092272 com.mysql.jdbc.PreparedStatement

10059 16794 402360 com.mysql.jdbc.PreparedStatement$ParseInfo

10058 29080 241392 java.util.regex.Pattern$TreeInfo

10058 16804 241392 com.mysql.jdbc.RowDataStatic

10058 16797 190616 com.webobjects.eocontrol.EOEnterpriseObject

10058 16797 160928 com.mysql.jdbc.ResultSetMetaData

10058 16794 179248 java.io.InputStream

9105 9125 946920 wk.cheetah.eof.CTLocation

8480 18911 135680 java.lang.Double

7820 13230 125120 com.webobjects.eocontrol.EOOrQualifier

7604 215135 121664 java.lang.StringBuilder

7360 7360 176640 com.webobjects.eoaccess.EODatabase$_ToManyRecord

7300 7706 233624 java.math.BigDecimal

7199 7214 806288 wk.cheetah.eof.CTCustomer

5088 31155 169736 java.util.Hashtable$Entry

4690 4709 637840 wk.cheetah.eof.CTMediaTemplate

4428 567855 123280 com.webobjects.foundation.NSKeyValueCoding$_KeyBinding

4207 4699 305912 java.lang.reflect.Field

3764 3765 451680 wk.cheetah.eof.CTUser

3615 3615 375960 wk.cheetah.eof.CTAccount

3578 11151 85872 java.sql.Date

3425 3425 82200 wk.eofextensions.EncodedString

2783 2783 311696 wk.cheetah.eof.CTAddress