asmhatreandClaude Sonnet 5.5
fc05eed4b5
Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01KqJyCidz3ZgRyHABv2GVJh
93 lines
4.5 KiB
Plaintext
93 lines
4.5 KiB
Plaintext
$ java -XX:-UseCompactObjectHeaders StringLayout (JDK 27)
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java.version = 27
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vm.flags = -XX:+EnableDynamicAgentLoading -XX:-UseCompactObjectHeaders
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# WARNING: Unable to attach Serviceability Agent. sun.jvm.hotspot.runtime.VM.isCompressedKlassPointersEnabled()
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# Field sizes: 4, 1, 1, 2, 2, 4, 4, 8, 8
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# Array element sizes: 4, 1, 1, 2, 2, 4, 4, 8, 8
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=== java.lang.String, the class
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java.lang.String object internals:
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OFF SZ TYPE DESCRIPTION VALUE
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0 8 (object header: mark) N/A
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8 4 (object header: class) N/A
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12 4 int String.hash N/A
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16 1 byte String.coder N/A
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17 1 boolean String.hashIsZero N/A
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18 2 (alignment/padding gap)
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20 4 byte[] String.value N/A
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Instance size: 24 bytes
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Space losses: 2 bytes internal + 0 bytes external = 2 bytes total
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=== one Latin-1 string and one UTF-16 string, field by field
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java.lang.String object internals:
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OFF SZ TYPE DESCRIPTION VALUE
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0 8 (object header: mark) 0x0000000000000001 (non-biasable; age: 0)
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8 4 (object header: class) 0x0017b7d8
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12 4 int String.hash 0
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16 1 byte String.coder 0
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17 1 boolean String.hashIsZero false
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18 2 (alignment/padding gap)
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20 4 byte[] String.value [104, 101, 108, 108, 111]
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Instance size: 24 bytes
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Space losses: 2 bytes internal + 0 bytes external = 2 bytes total
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java.lang.String object internals:
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OFF SZ TYPE DESCRIPTION VALUE
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0 8 (object header: mark) 0x0000000000000001 (non-biasable; age: 0)
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8 4 (object header: class) 0x0017b7d8
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12 4 int String.hash 0
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16 1 byte String.coder 1
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17 1 boolean String.hashIsZero false
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18 2 (alignment/padding gap)
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20 4 byte[] String.value [104, 0, -84, 32, 108, 0, 108, 0, 111, 0]
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Instance size: 24 bytes
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Space losses: 2 bytes internal + 0 bytes external = 2 bytes total
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=== the byte[] behind each
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[B object internals:
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OFF SZ TYPE DESCRIPTION VALUE
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0 8 (object header: mark) 0x0000000000000009 (non-biasable; age: 1)
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8 4 (object header: class) 0x00178240
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12 4 (array length) 5
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16 5 byte [B.<elements> N/A
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21 3 (object alignment gap)
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Instance size: 24 bytes
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Space losses: 0 bytes internal + 3 bytes external = 3 bytes total
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[B object internals:
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OFF SZ TYPE DESCRIPTION VALUE
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0 8 (object header: mark) 0x0000000000000001 (non-biasable; age: 0)
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8 4 (object header: class) 0x00178240
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12 4 (array length) 10
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16 10 byte [B.<elements> N/A
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26 6 (object alignment gap)
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Instance size: 32 bytes
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Space losses: 0 bytes internal + 6 bytes external = 6 bytes total
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=== footprint by length (String object + its byte[], via GraphLayout)
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chars content coder byte[].length String byte[] total
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0 ASCII 0 0 24 16 40
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0 U+00E9 0 0 24 16 40
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0 U+20AC 0 0 24 16 40
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1 ASCII 0 1 24 24 48
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1 U+00E9 0 1 24 24 48
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1 U+20AC 1 2 24 24 48
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5 ASCII 0 5 24 24 48
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5 U+00E9 0 5 24 24 48
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5 U+20AC 1 10 24 32 56
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10 ASCII 0 10 24 32 56
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10 U+00E9 0 10 24 32 56
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10 U+20AC 1 20 24 40 64
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20 ASCII 0 20 24 40 64
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20 U+00E9 0 20 24 40 64
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20 U+20AC 1 40 24 56 80
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40 ASCII 0 40 24 56 80
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40 U+00E9 0 40 24 56 80
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40 U+20AC 1 80 24 96 120
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100 ASCII 0 100 24 120 144
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100 U+00E9 0 100 24 120 144
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100 U+20AC 1 200 24 216 240
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1000 ASCII 0 1000 24 1016 1040
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1000 U+00E9 0 1000 24 1016 1040
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1000 U+20AC 1 2000 24 2016 2040
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