java: is the default document of a JTextField always a PlainDocument?

Is this always true?

new JTextField().getDocument() instanceof PlainDocument

B开发者_高级运维ecause I have read many examples of PlainDocument where they always create a new PlainDocument and then assign it to a JTextField, e.g. here.

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Ah, just checked out. The documentation says yes. The empty constructor always uses createDefaultModel() and createDefaultModel() always returns a PlainDocument.

-> Yes is the answer.

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Unless a class which implements the Document interface is passed to the JTextField constructor, the createDefaultModel() method is called, which does create a PlainDocument.