ktoso @ 月~/code/akka/akka-actor/target/classes [wip-ActorSelection-in-ALOD-ktoso*]
$ jol estimates -cp '.:/Users/ktoso/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.10.5.jar' akka.actor.ActorSelection

WARNING: Unable to attach Serviceability Agent. You can try again with super-user privileges. Use -Djol.tryWithSudo=true to try with sudo.
WARNING: VM details, e.g. object alignment, reference size, compressed references info will be guessed.

Running 64-bit HotSpot VM.
Using compressed oop with 3-bit shift.
Using compressed klass with 3-bit shift.
Objects are 8 bytes aligned.
Field sizes by type: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]
Array element sizes: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]

***** 32-bit VM: **********************************************************
objc[30707]: Class JavaLaunchHelper is implemented in both /Users/ktoso/.jenv/versions/1.8/bin/java and /Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/lib/libinstrument.dylib. One of the two will be used. Which one is undefined.
akka.actor.ActorSelection object internals:
 OFFSET  SIZE    TYPE DESCRIPTION                    VALUE
      0     8         (object header)                N/A
      8     4     int ActorSelection.hashCode        N/A
     12     1 boolean ActorSelection.bitmap$0        N/A
     13     3         (loss due to the next object alignment)
Instance size: 16 bytes (estimated, the sample instance is not available)
Space losses: 0 bytes internal + 3 bytes external = 3 bytes total

***** 64-bit VM: **********************************************************
akka.actor.ActorSelection object internals:
 OFFSET  SIZE    TYPE DESCRIPTION                    VALUE
      0    16         (object header)                N/A
     16     4     int ActorSelection.hashCode        N/A
     20     1 boolean ActorSelection.bitmap$0        N/A
     21     3         (loss due to the next object alignment)
Instance size: 24 bytes (estimated, the sample instance is not available)
Space losses: 0 bytes internal + 3 bytes external = 3 bytes total

***** 64-bit VM, compressed references enabled: ***************************
akka.actor.ActorSelection object internals:
 OFFSET  SIZE    TYPE DESCRIPTION                    VALUE
      0    12         (object header)                N/A
     12     4     int ActorSelection.hashCode        N/A
     16     1 boolean ActorSelection.bitmap$0        N/A
     17     7         (loss due to the next object alignment)
Instance size: 24 bytes (estimated, the sample instance is not available)
Space losses: 0 bytes internal + 7 bytes external = 7 bytes total

***** 64-bit VM, compressed references enabled, 16-byte align: ************
akka.actor.ActorSelection object internals:
 OFFSET  SIZE    TYPE DESCRIPTION                    VALUE
      0    12         (object header)                N/A
     12     4     int ActorSelection.hashCode        N/A
     16     1 boolean ActorSelection.bitmap$0        N/A
     17    15         (loss due to the next object alignment)
Instance size: 32 bytes (estimated, the sample instance is not available)
Space losses: 0 bytes internal + 15 bytes external = 15 bytes total