我使用命令行在solarix x86 - 64bit上运行weblogic服务器：
-Xrs -Xms4096m -Xmx4096m -XX:MaxPermSize=256m -da ...
所以最大堆大小应该是4G，但是经过一夜之后，它崩溃并产生了39G核心：
-bash-3.00$ ls -l core
-rw------- 1 user group 39017429722 Sep 27 19:47 core
我使用pmap转储核心内容：
$ pmap core
core 'core' of 21092: /opt/middleware/jdk1.6.0_21/bin/amd64/java -Xrs -Xms
0000000000400000 52K r-x-- /opt/middleware/jdk1.6.0_21/bin/amd64/java
000000000041C000 4K rw--- /opt/middleware/jdk1.6.0_21/bin/amd64/java
000000000041D000 2226208K rw---
0000000088225000 2097152K rw---
0000000108225000 4194304K rw---
0000000208225000 8388608K rw---
0000000408225000 16777216K rw--- [ heap ]
FFFFFD7EDF610000 512K rwx--
FFFFFD7EDF77A000 96K rw--- [ stack tid=147 ]
FFFFFD7EDF87B000 96K rw--- [ stack tid=146 ]
FFFFFD7EDF97C000 96K rw--- [ stack tid=145 ]
FFFFFD7EDFA7D000 96K rw--- [ stack tid=144 ]
.....
total 38102164K
正如你所看到的，那里有一个16G堆......为什么会这样？ java内存泄漏？
jmap dump：
-bash-3.00$ /opt/middleware/jdk1.6.0_21/bin/jmap -heap /opt/middleware/jdk1.6.0_21/bin/java -d64 core
Attaching to core core from executable /opt/middleware/jdk1.6.0_21/bin/java, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 17.0-b16
using thread-local object allocation.
Parallel GC with 4 thread(s)
Heap Configuration:
MinHeapFreeRatio = 40
MaxHeapFreeRatio = 70
MaxHeapSize = 4294967296 (4096.0MB)
NewSize = 1310720 (1.25MB)
MaxNewSize = 17592186044415 MB
OldSize = 5439488 (5.1875MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 21757952 (20.75MB)
MaxPermSize = 268435456 (256.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 1226899456 (1170.0625MB)
used = 396823336 (378.44022369384766MB)
free = 830076120 (791.6222763061523MB)
32.34359050852819% used
From Space:
capacity = 104726528 (99.875MB)
used = 2949120 (2.8125MB)
free = 101777408 (97.0625MB)
2.816020025031289% used
To Space:
capacity = 100728832 (96.0625MB)
used = 0 (0.0MB)
free = 100728832 (96.0625MB)
0.0% used
PS Old Generation
capacity = 2864709632 (2732.0MB)
used = 90771752 (86.56668853759766MB)
free = 2773937880 (2645.4333114624023MB)
3.1686196390043064% used
PS Perm Generation
capacity = 140509184 (134.0MB)
used = 139181296 (132.73362731933594MB)
free = 1327888 (1.2663726806640625MB)
99.05494576069846% used
其他信息：因此在此核心中加载了文件：
-bash-3.00$ grep so p.txt|sort -k 4
FFFFFD7FFF3B2000 228K r-x-- /lib/amd64/ld.so.1
FFFFFD7FFF3FB000 8K rwx-- /lib/amd64/ld.so.1
FFFFFD7FFF3FD000 8K rwx-- /lib/amd64/ld.so.1
FFFFFD7EE8100000 32K r-x-- /lib/amd64/libaio.so.1
FFFFFD7EE8118000 4K rw--- /lib/amd64/libaio.so.1
FFFFFD7EE8119000 4K rw--- /lib/amd64/libaio.so.1
FFFFFD7FFF1F0000 1252K r-x-- /lib/amd64/libc.so.1
FFFFFD7FFF339000 36K rw--- /lib/amd64/libc.so.1
FFFFFD7FFF342000 16K rw--- /lib/amd64/libc.so.1
FFFFFD7FFF350000 4K r-x-- /lib/amd64/libdl.so.1
FFFFFD7FFF361000 4K rw--- /lib/amd64/libdl.so.1
FFFFFD7FFE390000 8K r-x-- /lib/amd64/libdoor.so.1
FFFFFD7FFE3A2000 4K rw--- /lib/amd64/libdoor.so.1
FFFFFD7FFE1E0000 28K r-x-- /lib/amd64/libgen.so.1
FFFFFD7FFE1F7000 4K rw--- /lib/amd64/libgen.so.1
FFFFFD7FFE3E0000 16K r-x-- /lib/amd64/libm.so.1
FFFFFD7FFE3F3000 4K rw--- /lib/amd64/libm.so.1
FFFFFD7FFE250000 348K r-x-- /lib/amd64/libm.so.2
FFFFFD7FFE2B6000 24K rw--- /lib/amd64/libm.so.2
FFFFFD7FFE1C0000 48K r-x-- /lib/amd64/libmd.so.1
FFFFFD7FFE1DC000 4K rw--- /lib/amd64/libmd.so.1
FFFFFD7FFE1A0000 16K r-x-- /lib/amd64/libmp.so.2
FFFFFD7FFE1B4000 4K rw--- /lib/amd64/libmp.so.2
FFFFFD7FFE2C0000 664K r-x-- /lib/amd64/libnsl.so.1
FFFFFD7FFE376000 16K rw--- /lib/amd64/libnsl.so.1
FFFFFD7FFE37A000 36K rw--- /lib/amd64/libnsl.so.1
FFFFFD7EE8120000 32K r-x-- /lib/amd64/librt.so.1
FFFFFD7EE8138000 4K rw--- /lib/amd64/librt.so.1
FFFFFD7FFE220000 100K r-x-- /lib/amd64/libscf.so.1
FFFFFD7FFE249000 4K rw--- /lib/amd64/libscf.so.1
FFFFFD7FFF190000 60K r-x-- /lib/amd64/libsocket.so.1
FFFFFD7FFF1AF000 4K rw--- /lib/amd64/libsocket.so.1
FFFFFD7FFF3A0000 20K r-x-- /lib/amd64/libthread.so.1
FFFFFD7FFE200000 36K r-x-- /lib/amd64/libuutil.so.1
FFFFFD7FFE219000 4K rw--- /lib/amd64/libuutil.so.1
FFFFFD7FFF370000 36K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/jli/libjli.so
FFFFFD7FFF388000 8K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/jli/libjli.so
FFFFFD7EE80D0000 64K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libj2pkcs11.so
FFFFFD7EE80EF000 4K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libj2pkcs11.so
FFFFFD7FFDFE0000 188K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libjava.so
FFFFFD7FFE01E000 12K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libjava.so
FFFFFD7EE7DF0000 28K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libmanagement.so
FFFFFD7EE7E06000 4K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libmanagement.so
FFFFFD7EE82A0000 72K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libnet.so
FFFFFD7EE82C1000 8K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libnet.so
FFFFFD7EE8140000 32K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libnio.so
FFFFFD7EE8157000 4K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libnio.so
FFFFFD7FFE030000 68K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libverify.so
FFFFFD7FFE050000 8K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libverify.so
FFFFFD7FFDF70000 64K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libzip.so
FFFFFD7FFDF8F000 12K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/libzip.so
FFFFFD7FFDFC0000 40K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/native_threads/libhpi.so
FFFFFD7FFDFD9000 4K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/native_threads/libhpi.so
FFFFFD7FFDFDA000 20K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/native_threads/libhpi.so
FFFFFD7FFE400000 12932K r-x-- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/server/libjvm.so
FFFFFD7FFF0B2000 628K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/server/libjvm.so
FFFFFD7FFF14F000 112K rw--- /opt/middleware/jdk1.6.0_21/jre/lib/amd64/server/libjvm.so
FFFFFD7FFE3B0000 60K r-x-- /usr/lib/amd64/libCrun.so.1
FFFFFD7FFE3CE000 8K rw--- /usr/lib/amd64/libCrun.so.1
FFFFFD7FFE3D0000 24K rw--- /usr/lib/amd64/libCrun.so.1
FFFFFD7EE8070000 28K r-x-- /usr/lib/amd64/libcryptoutil.so.1
FFFFFD7EE8087000 8K rw--- /usr/lib/amd64/libcryptoutil.so.1
FFFFFD7EE8090000 136K r-x-- /usr/lib/amd64/libpkcs11.so.1
FFFFFD7EE80C2000 4K rw--- /usr/lib/amd64/libpkcs11.so.1
FFFFFD7EE80C3000 4K rw--- /usr/lib/amd64/libpkcs11.so.1
FFFFFD7FFF1C0000 4K r-x-- /usr/lib/amd64/libsched.so.1
FFFFFD7EE8010000 304K r-x-- /usr/lib/security/amd64/pkcs11_softtoken_extra.so.1
FFFFFD7EE806C000 12K rw--- /usr/lib/security/amd64/pkcs11_softtoken_extra.so.1
答案 0 :(得分：1)
-Xmx4096m是java Heap的大小。 核心转储是关于整个Java虚拟机地址空间的过程。
根据操作系统的不同，您可以获得比预期更大的虚拟寻址空间。因此转储可能更大。
例如，WindowsXP的每个进程都有4GB的地址空间，即使你在256MB的RAM上运行也是如此。
我认为核心转储大小取决于Java VM + O.S.实现。 例如，Solaris和Linux核心转储根本没有任何共同之处。
<强>更新 两种选择： 您使用的是本机库（即非标准的东西）吗？ 如果是，请禁用本机扩展并进行一些测试。同样禁用Java NIO可能有所帮助。
如果你使用的是普通的WebLogic，请试试你的支持：64bit它在大型部署中是如此常见，而你似乎有一个非常大的（你有很多内存，我甚至看过:) / p>