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Code and session notes for blog post: Exploring HotSpot runtime data with HSDB http://rednaxelafx.iteye.com/blog/1847971
D:\test>jdb -XX:+UseSerialGC -Xmx10m -J-Duser.country=en.US
Initializing jdb ...
> stop in Test.fn
Deferring breakpoint Test.fn.
It will be set after the class is loaded.
> run Main
run Main
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
VM Started: Set deferred breakpoint Test.fn
Breakpoint hit: "thread=main", Test.fn(), line=5 bci=0
5 Test2 t3 = new Test2();
main[1] next
Step completed: > "thread=main", Test.fn(), line=6 bci=8
6 }
main[1]
D:\test>jps
4328 Main
9064 Jps
7716 TTY
D:\test>java -cp .;%JAVA_HOME%/lib/sa-jdi.jar sun.jvm.hotspot.HSDB
hsdb> universe
Heap Parameters:
Gen 0: eden [0x00000000fa400000,0x00000000fa4aad68,0x00000000fa6b0000) space capacity = 2818048, 24.831088753633722 used
from [0x00000000fa6b0000,0x00000000fa6b0000,0x00000000fa700000) space capacity = 327680, 0.0 used
to [0x00000000fa700000,0x00000000fa700000,0x00000000fa750000) space capacity = 327680, 0.0 usedInvocations: 0
Gen 1: old [0x00000000fa750000,0x00000000fa750000,0x00000000fae00000) space capacity = 7012352, 0.0 usedInvocations: 0
perm [0x00000000fae00000,0x00000000fb078898,0x00000000fc2c0000) space capacity = 21757952, 11.90770160721009 usedInvocations: 0
hsdb> scanoops 0x00000000fa400000 0x00000000fc2c0000 Test2
0x00000000fa49a710 Test2
0x00000000fa49a730 Test2
0x00000000fa49a740 Test2
Error: sun.jvm.hotspot.debugger.DebuggerException: Windbg Error: ReadVirtual failed!
hsdb> revptrs 0x00000000fa49a710
Computing reverse pointers...
Done.
null
Oop for java/lang/Class @ 0x00000000fa499b00
hsdb> whatis 0x00000000fa499b00
Address 0x00000000fa499b00: In thread-local allocation buffer for thread "main" (1) [0x00000000fa48f490,0x00000000fa49a750,0x00000000fa49d118)
hsdb> inspect 0x00000000fa499b00
instance of Oop for java/lang/Class @ 0x00000000fa499b00 @ 0x00000000fa499b00 (size = 120)
<<Reverse pointers>>:
t1: Oop for Test2 @ 0x00000000fa49a710 Oop for Test2 @ 0x00000000fa49a710
hsdb> revptrs 0x00000000fa49a730
Oop for Test @ 0x00000000fa49a720
hsdb> whatis 0x00000000fa49a720
Address 0x00000000fa49a720: In thread-local allocation buffer for thread "main" (1) [0x00000000fa48f490,0x00000000fa49a750,0x00000000fa49d118)
hsdb> inspect 0x00000000fa49a720
instance of Oop for Test @ 0x00000000fa49a720 @ 0x00000000fa49a720 (size = 16)
<<Reverse pointers>>:
_mark: 1
t2: Oop for Test2 @ 0x00000000fa49a730 Oop for Test2 @ 0x00000000fa49a730
hsdb> revptrs 0x00000000fa49a740
null
hsdb> mem 0x000000000287f7f0 30
0x000000000287f7f0: 0x0000000002886298
0x000000000287f7f8: 0x0000000002893ca5
0x000000000287f800: 0x0000000002893ca5
0x000000000287f808: 0x000000000287f808
0x000000000287f810: 0x00000000fb077f58
0x000000000287f818: 0x000000000287f860
0x000000000287f820: 0x00000000fb078360
0x000000000287f828: 0x0000000000000000
0x000000000287f830: 0x00000000fb077f78
0x000000000287f838: 0x0000000000000000
0x000000000287f840: 0x000000000287f860
0x000000000287f848: 0x000000000287f8a8
0x000000000287f850: 0x0000000002886298
0x000000000287f858: 0x00000000fa49a740
0x000000000287f860: 0x00000000fa49a720
0x000000000287f868: 0x000000000287f868
0x000000000287f870: 0x00000000fb077039
0x000000000287f878: 0x000000000287f8c0
0x000000000287f880: 0x00000000fb077350
0x000000000287f888: 0x0000000000000000
0x000000000287f890: 0x00000000fb077060
0x000000000287f898: 0x000000000287f860
0x000000000287f8a0: 0x000000000287f8c0
0x000000000287f8a8: 0x000000000287f9a0
0x000000000287f8b0: 0x000000000288062a
0x000000000287f8b8: 0x00000000fa49a720
0x000000000287f8c0: 0x00000000fa498ea8
0x000000000287f8c8: 0x0000000000000000
0x000000000287f8d0: 0x0000000000000000
0x000000000287f8d8: 0x0000000000000000
hsdb> jstack -v
Deadlock Detection:
No deadlocks found.
Thread 6: (state = BLOCKED, current Java SP = null
)
Locked ownable synchronizers:
- None
Thread 5: (state = BLOCKED, current Java SP = null
)
Locked ownable synchronizers:
- None
Thread 4: (state = BLOCKED, current Java SP = 0x0000000005f6ef50
)
- java.lang.Object.wait(long) @bci=0, pc=0x0000000002898c61, methodOop=0x00000000fae02958 (Interpreted frame)
- java.lang.ref.ReferenceQueue.remove(long) @bci=44, line=135, pc=0x0000000002886298, methodOop=0x00000000faed0a60 (Interpreted frame)
- java.lang.ref.ReferenceQueue.remove() @bci=2, line=151, pc=0x0000000002886473, methodOop=0x00000000faed0b40 (Interpreted frame)
- java.lang.ref.Finalizer$FinalizerThread.run() @bci=3, line=177, pc=0x0000000002886473, methodOop=0x00000000faed21d8 (Interpreted frame)
Locked ownable synchronizers:
- None
Thread 3: (state = BLOCKED, current Java SP = 0x0000000005a1f730
)
- java.lang.Object.wait(long) @bci=0, pc=0x0000000002898c61, methodOop=0x00000000fae02958 (Interpreted frame)
- java.lang.Object.wait() @bci=2, line=503, pc=0x0000000002886298, methodOop=0x00000000fae02b68 (Interpreted frame)
- java.lang.ref.Reference$ReferenceHandler.run() @bci=46, line=133, pc=0x0000000002886298, methodOop=0x00000000faecf620 (Interpreted frame)
Locked ownable synchronizers:
- None
Thread 1: (state = BLOCKED, current Java SP = 0x000000000287f808
)
- Test.fn() @bci=8, line=6, pc=0x0000000002893ca5, methodOop=0x00000000fb077f78 (Interpreted frame)
- Main.main(java.lang.String[]) @bci=9, line=4, pc=0x0000000002886298, methodOop=0x00000000fb077060 (Interpreted frame)
Locked ownable synchronizers:
- None
hsdb> inspect 0x00000000fb077f58
Error: sun.jvm.hotspot.debugger.UnalignedAddressException: 100011
hsdb> inspect 0x00000000fb077f78
instance of Method fn()V@0x00000000fb077f78 @ 0x00000000fb077f78 @ 0x00000000fb077f78 (size = 136)
_mark: 1
_constMethod: ConstMethod fn()V@0x00000000fb077f08 @ 0x00000000fb077f08 Oop @ 0x00000000fb077f08
_constants: ConstantPool for Test @ 0x00000000fb077c68 Oop @ 0x00000000fb077c68
_method_size: 17
_max_stack: 2
_max_locals: 2
_size_of_parameters: 1
_access_flags: 1
hsdb> inspect 0x00000000fb077f08
instance of ConstMethod fn()V@0x00000000fb077f08 @ 0x00000000fb077f08 @ 0x00000000fb077f08 (size = 112)
_mark: 1
_method: Method fn()V@0x00000000fb077f78 @ 0x00000000fb077f78 Oop @ 0x00000000fb077f78
_exception_table: [I @ 0x00000000fae01d50 Oop for [I @ 0x00000000fae01d50
_constMethod_size: 14
_flags: 5
_code_size: 9
_name_index: 18
_signature_index: 12
_generic_signature_index: 0
_code_size: 9
hsdb> whatis 0x00000000fb077f58
Address 0x00000000fb077f58: In perm generation perm [0x00000000fae00000,0x00000000fb078898,0x00000000fc2c0000) space capacity = 21757952, 11.90770160721009 used
hsdb> print 0x00000000fb077f78
public void fn() @0x00000000fb077f78
Holder Class
public class Test @0x00000000fb078100
Bytecode
line bci bytecode
5 0 new #2 [Class Test2]
5 3 dup
5 4 invokespecial #1 [Method Test2.<init>()V]
5 7 astore_1
6 8 return
Constant Pool
Constant Pool of [public class Test @0x00000000fb078100] @0x00000000fb077c68
hsdb> mem 0x00000000fb077f50 2
0x00000000fb077f50: 0x4c0001b7590200ca
0x00000000fb077f58: 0x00000000004105b1
hsdb> class Test
Test @0x00000000fb078100
hsdb> print 0x00000000fb078100
public class Test @0x00000000fb078100
Super Class
public class java.lang.Object @0x00000000fae02df8
Fields
static Test2 t1; (offset = 112)
Test2 t2; (offset = 12)
Methods
public void <init>() @0x00000000fb077e80;
static void <clinit>() @0x00000000fb078058;
public void fn() @0x00000000fb077f78;
Constant Pool
Constant Pool of [public class Test @0x00000000fb078100] @0x00000000fb077c68
hsdb>
public class Main {
public static void main(String[] args) {
Test test = new Test();
test.fn();
}
}
hsdb> mem 0x00000000fb077030 2
0x00000000fb077030: 0x4c0001b7590200bb
0x00000000fb077038: 0x214103b10002b62b
0x00000000fb077030: bb 00 02 new <cp index #2> [Class Test]
0x00000000fb077033: 59 dup
0x00000000fb077034: b7 01 00 invokespecial <cp cache index #1> [Method Test.<init>()V]
0x00000000fb077037: 4c astore_1
0x00000000fb077038: 2b aload_1
0x00000000fb077039: b6 02 00 invokevirtual <cp cache index #2> [Method Test.fn()V]
0x00000000fb07703c: b1 return
0x000000000287f7f0: 0x0000000002886298
0x000000000287f7f8: 0x0000000002893ca5
0x000000000287f800: 0x0000000002893ca5
-------------------------------------------------------------------------------------------------------------
Stack frame for Test.fn() @bci=8, line=6, pc=0x0000000002893ca5, methodOop=0x00000000fb077f78 (Interpreted frame)
0x000000000287f808: 0x000000000287f808 expression stack bottom <- rsp
0x000000000287f810: 0x00000000fb077f58 bytecode pointer = 0x00000000fb077f50 (base) + 8 (bytecode index) in PermGen
0x000000000287f818: 0x000000000287f860 pointer to locals
0x000000000287f820: 0x00000000fb078360 constant pool cache = ConstantPoolCache for Test in PermGen
0x000000000287f828: 0x0000000000000000 method data oop = null
0x000000000287f830: 0x00000000fb077f78 method oop = Method for Test.fn()V in PermGen
0x000000000287f838: 0x0000000000000000 last Java stack pointer (not set)
0x000000000287f840: 0x000000000287f860 old stack pointer (saved rsp)
0x000000000287f848: 0x000000000287f8a8 old frame pointer (saved rbp) <- rbp
0x000000000287f850: 0x0000000002886298 return address = in interpreter codelet "return entry points" [0x00000000028858b8, 0x00000000028876c0) 7688 bytes
0x000000000287f858: 0x00000000fa49a740 local[1] "t3" = Oop for Test2 in NewGen
0x000000000287f860: 0x00000000fa49a720 local[0] "this" = Oop for Test in NewGen
-------------------------------------------------------------------------------------------------------------
0x000000000287f868: 0x000000000287f868
0x000000000287f870: 0x00000000fb077039
0x000000000287f878: 0x000000000287f8c0
0x000000000287f880: 0x00000000fb077350
0x000000000287f888: 0x0000000000000000
0x000000000287f890: 0x00000000fb077060
0x000000000287f898: 0x000000000287f860
0x000000000287f8a0: 0x000000000287f8c0
0x000000000287f8a8: 0x000000000287f9a0
0x000000000287f8b0: 0x000000000288062a
0x000000000287f8b8: 0x00000000fa49a720
0x000000000287f8c0: 0x00000000fa498ea8
0x000000000287f8c8: 0x0000000000000000
0x000000000287f8d0: 0x0000000000000000
0x000000000287f8d8: 0x0000000000000000
0x000000000287f7f0: 0x0000000002886298
0x000000000287f7f8: 0x0000000002893ca5
0x000000000287f800: 0x0000000002893ca5
0x000000000287f808: 0x000000000287f808
0x000000000287f810: 0x00000000fb077f58
0x000000000287f818: 0x000000000287f860
0x000000000287f820: 0x00000000fb078360
0x000000000287f828: 0x0000000000000000
0x000000000287f830: 0x00000000fb077f78
0x000000000287f838: 0x0000000000000000
0x000000000287f840: 0x000000000287f860
0x000000000287f848: 0x000000000287f8a8
0x000000000287f850: 0x0000000002886298
0x000000000287f858: 0x00000000fa49a740
-------------------------------------------------------------------------------------------------------------
Stack frame for Main.main(java.lang.String[]) @bci=9, line=4, pc=0x0000000002886298, methodOop=0x00000000fb077060 (Interpreted frame)
0x000000000287f860: 0x00000000fa49a720 expression stack[0] = Oop for Test in NewGen
0x000000000287f868: 0x000000000287f868 expression stack bottom
0x000000000287f870: 0x00000000fb077039 bytecode pointer = 0x00000000fb077030 (base) + 9 (bytecode index) in PermGen
0x000000000287f878: 0x000000000287f8c0 pointer to locals
0x000000000287f880: 0x00000000fb077350 constant pool cache = ConstantPoolCache for Main in PermGen
0x000000000287f888: 0x0000000000000000 method data oop = null
0x000000000287f890: 0x00000000fb077060 method oop = Method for Main.main([Ljava/lang/String;)V in PermGen
0x000000000287f898: 0x000000000287f860 last Java stack pointer
0x000000000287f8a0: 0x000000000287f8c0 old stack pointer
0x000000000287f8a8: 0x000000000287f9a0 old frame pointer
0x000000000287f8b0: 0x000000000288062a return address = in StubRoutines
0x000000000287f8b8: 0x00000000fa49a720 local[1] "test" = Oop for Test in NewGen
0x000000000287f8c0: 0x00000000fa498ea8 local[0] "args" = Oop for java.lang.String[] in NewGen
-------------------------------------------------------------------------------------------------------------
0x000000000287f8c8: 0x0000000000000000
0x000000000287f8d0: 0x0000000000000000
0x000000000287f8d8: 0x0000000000000000
public class Test {
static Test2 t1 = new Test2();
Test2 t2 = new Test2();
public void fn() {
Test2 t3 = new Test2();
}
}
class Test2 {
}
hsdb> mem 0x00000000fb077f50 2
0x00000000fb077f50: 0x4c0001b7590200ca
0x00000000fb077f58: 0x00000000004105b1
0x00000000fb077f50: bb 00 02 new <cp index #2> [Class Test2]
0x00000000fb077f53: 59 dup
0x00000000fb077f54: b7 01 00 invokespecial <cp cache index #1> [Method Test2.<init>()V]
0x00000000fb077f57: 4c astore_1
0x00000000fb077f58: b1 return
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