具体信息如下：

RES是1.6G

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

28527 root 20 0 12.1g 1.6g 13m S 0.0 5.0 0:52.19 java

但是used:堆用了262M， concurrent mark-sweep generation用了48M，interned String占了250多M

Attaching to process ID 28527, please wait...

Debugger attached successfully.

Server compiler detected.

JVM version is 25.51-b03

using parallel threads in the new generation.

using thread-local object allocation.

Concurrent Mark-Sweep GC

Heap Configuration:

MinHeapFreeRatio = 40

MaxHeapFreeRatio = 70

MaxHeapSize = 8589934592 (8192.0MB)

NewSize = 4294967296 (4096.0MB)

MaxNewSize = 4294967296 (4096.0MB)

OldSize = 4294967296 (4096.0MB)

NewRatio = 2

SurvivorRatio = 8

MetaspaceSize = 21807104 (20.796875MB)

CompressedClassSpaceSize = 1073741824 (1024.0MB)

MaxMetaspaceSize = 17592186044415 MB

G1HeapRegionSize = 0 (0.0MB)

Heap Usage:

New Generation (Eden + 1 Survivor Space):

capacity = 3865509888 (3686.4375MB)

used = 274884512 (262.1502990722656MB)

free = 3590625376 (3424.2872009277344MB)

7.1112096454169% used

Eden Space:

capacity = 3436052480 (3276.875MB)

used = 274884512 (262.1502990722656MB)

free = 3161167968 (3014.7247009277344MB)

8.000009126752337% used

From Space:

capacity = 429457408 (409.5625MB)

used = 0 (0.0MB)

free = 429457408 (409.5625MB)

0.0% used

To Space:

capacity = 429457408 (409.5625MB)

used = 0 (0.0MB)

free = 429457408 (409.5625MB)

0.0% used

concurrent mark-sweep generation:

capacity = 4294967296 (4096.0MB)

used = 50954384 (48.59388732910156MB)

free = 4244012912 (4047.4061126708984MB)

1.1863742023706436% used

22283 interned Strings occupying 2737728 bytes.