When println() is displaying an Object, which one of the Object's
methods does println() call?
- add()
- toString()
- equals()
- compareTo()
- String()
I'm Not Sure whether its toString or String can someone please clarify?
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brainless coder
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user3847508
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I would really appreciate it if someone could help me. I'm just a 12 year old. My parents are forcing me to go learn java at this prep school. – user3847508 Jun 02 '15 at 05:08
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Look up the javadoc for `Object`. Which of the methods you've listed does it have and which doesn't it have. Go by elimination. Then look up what each one does. – Sotirios Delimanolis Jun 02 '15 at 05:12
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Why dont you tell them I have tried! – user3847508 Jun 02 '15 at 05:24
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See http://stackoverflow.com/questions/8555771/why-is-the-tostring-method-being-called-when-i-print-an-object – Raedwald Mar 26 '16 at 12:43
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Possible duplicate of http://stackoverflow.com/questions/27647567/how-to-support-println-in-a-class – Raedwald Mar 26 '16 at 14:11
2 Answers
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None of them.
If you pass an Object to println() this
println(Object o)
will be called which calls the String.valueOf(o) actually.
But then String.valueOf(o) calls the o.toString()if the o is not null.
So you can say its toString() indirectly.
Saif
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When using the signature println(Object) the toString() method is being used to output the string representation of that object.
When toString() is called on an object you've defined it will cascade up the hierarchy of superclasses until reaching java.lang.Object given that there is no overridden toString() method in any intermediate superclasses or the initial class. Upon reaching java.lang.Object the system will call the base toString() method which prints the String literal representation of that Object and is the reason why you will see some memory address in the output.
James S
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