public class Test{
int i;
Test(){
System.out.println(i);
}
public static void main(String[] args){
Test obj=new Test();
}
}
Output=0
P.S: I am naive in Java so this question could be very silly. I am expecting your support. Thanks
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That's how Java is defined. Read the JLR -- the Java Language Reference -- for the details.Hovercraft Full Of Eels– Hovercraft Full Of Eels2016-03-23 21:22:55 +00:00Commented Mar 23, 2016 at 21:22
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The default value of an int is 0Abdelhak– Abdelhak2016-03-23 21:22:59 +00:00Commented Mar 23, 2016 at 21:22
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When you declare an int as a "field" (class variable), It initialize automatically with value "0", but when belongs to other method, is "null"M. Mariscal– M. Mariscal2016-03-23 21:50:21 +00:00Commented Mar 23, 2016 at 21:50
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@Abdelhak Instance variable belongs to Object and static variable belongs to class. In the above case variable i belongs to whom since there is no object and i is not a static variable.Ravi Shankar– Ravi Shankar2016-03-23 22:21:44 +00:00Commented Mar 23, 2016 at 22:21
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Are you sure this program has any output? I would not expect it to.Louis Wasserman– Louis Wasserman2016-03-23 22:41:56 +00:00Commented Mar 23, 2016 at 22:41
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2 Answers
Static/Instance fields which are not initialized will be set to a default value by the compiler.
The table bellow indicates the default value for data types:
+--------------------------+----------------------------+
| Data Type | Default Value (for fields) |
+--------------------------+----------------------------+
| byte | 0 |
| short | 0 |
| int | 0 |
| long | 0L |
| float | 0.0f |
| double | 0.0d |
| char | '\u0000' |
| String (or any object) | null |
| boolean | false |
+--------------------------+----------------------------+
For more information, you can see the doc here
Comments
See, every Instance-Variable or Class-Variable initialized by it's default value
In case instance-variable is some Reference type then it will be always assigned with it's default value by
null
So, here in your case int is primitive type whose default value is 0(zero) that's the reason you get 0 in out-put.
