what is the use of toString() in java [duplicate]

This question already has answers here: 开发者_如何学Python Closed 12 years ago.

Possible Duplicates:

What are the original reasons for ToString() in Java and .NET?

when to use toString() method

what is main use of toString() in java

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As the javadoc says:

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

You can use this for:

• logging
• debugging
• representing in UI

etc.

However, it is advisable that you use it only for internal purposes, like logging and debugging.

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The main use of toString() is allowing arbitrary objects to be printed or logged.

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In short, you come up with a String representation of your class, so you'll see meaningful values in your logs or when debugging instead of the default YourClass@38c313. This representation is completely arbitrary.

For details, have a look at Item 10 in Effective Java, it has a couple of pretty good advices.

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Just to add, sometimes it is useful to convert some object to a textual representation, and then define a constructor which can create an object out of this textual representation, something like

public Foo(String textualRep) {

}

I've seen this approach somewhere in used in the JDK but can't remember where.