• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.8
• Operating System version: window 7
• Java version: 1.8.0_261

Steps to reproduce this issue

1. User Proxy to create new instance of any interface
2. System full GC
3. Check PermSpace unuse size

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

PermSpace used size will no increase
永久区使用空间不会明显增长

What do you expected from the above steps？

Actual Result

PermSpace used size will increase after very Full GC, which cause a OutOfMemoryError [PermSpace]
永久区使用空间在每次full GC之后都会有所增加，直到永久区内存溢出。

If there is an exception, please attach the exception trace:
java.lang.RuntimeException: by java.lang.OutOfMemoryError: PermGen space

Just put your stack trace here!

java.lang.RuntimeException: by java.lang.OutOfMemoryError: PermGen space