Memory Usage in static Method

[arun mahajan]

Hello,

class A
{
String retval = B.x("Arun");
}
Class B
{
public static String x(String abc)
{
String val = "";
val="Thanks"+abc;
return val;
}
}

I have following questions for the above scenario:

Q1.: When will class B comes in memory..is it when A is calling static method of B?
Q2.: How I can release the memory of this class B as after getting the return value it is no more used.
Q3.: Is it that when garbage collector will run it release this class memory as this is no more in use? Does it mean that gc() release those objects also which are not used for sometime.
regards,
Arun

[Pradyumna Hari]

Hi arun,
Here are the answers :
(1) Yes. Class is loaded in memory when there is reference to any of its static fields/methods or when an instance of class is created.
(2) The memory occupied by class B would be reclaimed by Garbage collector as there is no reference to any object of class B.
(3) Yes. GC will release memory of those objects for which there does not exist any reference. When would the garbage collector run is either when your jvm is falling short of memory allocated to it by cpu or when you force the GC to run ( though it does not relent to any force, I suppose )

[arun mahajan]

Thanks for the answer...tha which is preferable & efficent:
Method 1 or Method 2. or both are same?:-
Method1

  
class A
{
  String retval = B.x("Arun");
}
Class B
{
 public static String x(String abc)
 {
   String val = "";
   val="Thanks"+abc;
   return val;
 }
}

Method2

  
class A
{
  B y = new B();
  String retval = y.x("Arun");
  y=null;
}
Class B
{
 public String x(String abc)
 {
   String val = "";
   val="Thanks"+abc;
   return val;
 }
}

[Ilja Preuss]

Except that 2) wouldn't compile, 1) would probably be slightly more efficient regarding runtime performance.
But why do you care? Do you have encountered an actual performance/memory usage problem?

[arun mahajan]

Thanks Ilja for the reply..No I am not facing any performance problems but perhaps just was more worried on it..Thanks anyway..
One thing I was not able to understand that why Method 2 won't compile..perhaps it is not properly written i modeified it in following way and found working..Is that was the only reason or you want to point out something special..
Regards,
Arun

public class A
{
public A()
{
B y = new B();
String retval = y.x("Arun");
System.out.println("retval: "+retval);
y=null;
}
public static void main(String[] args)
{
A aa = new A();
}
}
class B
{
public B(){}
public String x(String abc)
{
String val = "";
val="Thanks "+abc;
return val;
}
}
  

[Ilja Preuss]

Originally posted by arun mahajan:
Thanks Ilja for the reply..No I am not facing any performance problems but perhaps just was more worried on it..Thanks anyway..

You should probably be more worried about maintainability and extensibility...
Time to reiterate the Three Rules Of Optimization:
1. Don't
2. (for experts only) Don't - yet
3. (if and only if you really need to optimize) Use a profiler to find the actual bottleneck - it isn't where you think it is.

One thing I was not able to understand that why Method 2 won't compile..perhaps it is not properly written i modeified it in following way and found working..Is that was the only reason or you want to point out something special..

In your original post, you forgot the method body in class A - that's all.