doubt in finally variable

[raja ram]

Hi,

What is the meaning of statement "final variables can still be manipulated unless its immutable"

i know that final variables do not take default values however they should and must be initalized before the completion of constructor. like

public class test{

final int i;

test(){ i=10' }
}

will work with out any problem but what is the meaning of above statement
can any body give me example for this.

Thanks

[Jesper de Jong]

Your example works because the variable i has not yet been initialized at declaration. If you change it like this, it will not compile anymore:

public class Test {
    final int i = 10;
 
    Test() {
        i = 10;  // Error, can't change the value of a final variable that's already initialized
    }
}

But I don't think that is what the original statement is about.

This is what it means: You cannot change the value of a final variable after it has been initialized, but you can change the content of the object that the variable refers to (unless the object is immutable). For example:

public class Test {
    final StringBuffer sb = new StringBuffer();
 
    public void someMethod() {
        // Note that sb is final, but we can change the content of the StringBuffer object
        sb.append("Hello");
 
        // This, however, does not work, because sb is final
        sb = new StringBuffer();
    }
}

[ March 27, 2008: Message edited by: Jesper Young ]

[raja ram]

Hi,

Thanks for the reply. yes what you are saying is correct but my doubt was what the statement means i am aware of the concepts you are explaining but what actually this statement means can any body explain me.

Thanks

[Gaurav Joshi]

Any ways final variables whose value is not initialized during declaration are called blank final variable

[raja ram]

Hi,

any updates on this

Thanks

[Sandeep Bhandari]

Can share some more lines in front and after it from the source you got it.

[raja ram]

Hi,

I found this line in the SCWCD book of HFSJ. there are no code example but this line when discussing about the context-param.

Thanks

[Sandeep Bhandari]

I would rephrase the line as:

Final references can still be manipulated unless underlying object is immutable