Spring bean life cycle and scope? SPIRNG beans dependent on each other? JVM Oom? JVM monitoring tools? ThreadLocal principle

Oom?

Java.lang.OutOfMemoryError:java head space heap memory overflow

Java.lang.OutOfMemoryError:Permgen Space Java Eternal Overflow, that is, methods to overflow, generally because of the emergence of a large number of classes and JSPs, or the use of Cglib reflection mechanism,

This can be resolved by changing the size of the method area and modifying it in the form of a similar-xx:permsize=64m-xx:maxpermsize=256m. In addition, too many constants, especially strings, can cause the method area to overflow.

Spring bean life cycle and scope? SPIRNG beans dependent on each other? JVM Oom? JVM monitoring tools? ThreadLocal principle