why not able to define a method inside of run() method of thread

Question

the first example is possible, but example 2 is not possible and results in "illegal start of expression" error message from the compiler. why is it not possible to define a method inside of the run() method?

example 1

 public class TextUpdater implements Runnable {

    public void inter(){

    }

    @Override
    public void run() {

        inter();

    }

   }
}

example 2, not possible

 public class TextUpdater implements Runnable {

    @Override
    public void run() {

       public void inter(){  // results in error

       }

   }
}

This may be perfectly legal in other languages, but not in Java. — mavrosxristoforos, Sep 30 '13 at 08:07
Umm ... this is a bit like asking why a bicycle doesn't have wings. — Stephen C, Sep 30 '13 at 08:11
possible duplicate of [Function within a function- Java](http://stackoverflow.com/questions/7097275/function-within-a-function-java) — Dennis Meng, Mar 06 '14 at 05:16

score 4 · Answer 1 · answered Sep 30 '13 at 08:04

4

Java does not let you define a method inside a method. It doesn't even have any semantic rules for what that would do. What are you expecting example 2 to do?

It's clear what example 1 does. You create a method called inter with an empty body. Then, in run, you call it.

But what should 2 do? You create a method inter inside run. So what would that do? When would you call it?

answered Sep 30 '13 at 08:04

David Schwartz

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2

+1 for the questions, actually those are answers :) – Suresh Atta Sep 30 '13 at 08:07
this is a good answer in the way of classic philosophy – Kevik Oct 01 '13 at 01:02

score 1 · Answer 2 · answered Sep 30 '13 at 08:04

1

Because you cannot define a method inside a method.

answered Sep 30 '13 at 08:04

Maroun

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score 1 · Accepted Answer · edited May 23 '17 at 11:58

1

If you actually declare a method within a method it will always result in an error. Java is strictly object-oriented and it requires methods to belong to a class. In other words, you have to declare your methods in class. JavaScript, Python and other object-oriented languages loosen this strict rule, but Java does not. Read this thread on stackoverflow. It is almost exactly the same topic.

edited May 23 '17 at 11:58

Community

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answered Sep 30 '13 at 08:17

Florian R. Klein

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score 0 · Answer 4 · answered Sep 30 '13 at 08:05

0

Not possible to create a method inside another method.

answered Sep 30 '13 at 08:05

AppX

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score 0 · Answer 5 · answered Sep 30 '13 at 08:05

0

run() is a method, you just can not define new methods inside a method. Methods are defining in class section not inside methods

answered Sep 30 '13 at 08:05

Lebedevsd

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why not able to define a method inside of run() method of thread

5 Answers5