Java: Initialiasing objects inside or outside the constructor?

Question

I am interested in understanding whether there is any difference between initialising an object inside or outside the constructor

public class HTMLTable {
int value1;
Scanner user_input;

  public HTMLTable () {
    user_input = new Scanner(System.in);
    value = user_input.next();
  }
}

Instead of:

public class HTMLTable {
int value1;
Scanner user_input = new Scanner(System.in);

  public HTMLTable () {
    value = user_input.next();
  }
}

Can someone explain?

And http://stackoverflow.com/questions/3918578/should-i-initialize-variable-within-constructor-or-outside-constructor — Steve Chambers, Mar 11 '13 at 10:57

sp00m · Accepted Answer · 2013-03-11T11:00:10.123

5

There's no difference: the compiler will move any outside initialization within the constructor.

See Java for a Nutshell, section 3.2.4: Field Defaults and Initializers.

edited Mar 11 '13 at 11:00

answered Mar 11 '13 at 10:55

sp00m

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score 2 · Answer 2 · answered Mar 11 '13 at 10:57

2

There is no difference. Compiler would move initialization code (like in 2nd example) into constructor body anyway. Chose this or that variant depending on readability of the code.

answered Mar 11 '13 at 10:57

Alexei Kaigorodov

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Java: Initialiasing objects inside or outside the constructor?

2 Answers2