getClass method in java

How is it that the getC开发者_如何学Pythonlass method in Object class is capable of dynamically returning Class?

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It doesn't return the class name - it returns the Class representing that object's type. Each object "knows" what type it really is - that's how casts can work or fail depending on the execution-time type. Object.getClass() just retrieves the relevant information from the object.

If you have a class which only contains a single int, each object will still take up more than 4 bytes in memory: there's effectively an object "header" containing things like a reference to the object's actual type, information to do with the monitor associated with that object etc.

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And there's nothing dynamic about it. The class of the object can never change.