18_ class namespace and unloading Detailed and use jvisualvm

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Class unloading

The resulting output is:

How to see the original class loader and loaded class has not been unloaded?

After the operation, the result did not change
Expository not unloaded
so, explicitly calling gc

The output is:

class is unloaded
if the three reference not set to null?

Operational results are:

not unloaded
because when you call gc when the reference is still pointing to the original object
after the call, only to point to the new object, the gc does not make sense
, then, the gc another location

In this case, the class is unloaded

Use the tool to see jvisualvm