CODEWITHSUNDEEP
javavariablesfinal
user3371172
user3371172

Reputation: 31

assign the final variable with the function return type

In java i tried to assign the final variable with the function return value. But i got the compilation errors. Can anyone help me what is causing the errors here?

the code is like this:

public class A{
  private static final set<String> set1 = getSet();
  private Static Set<String> getSet(){
     Vector<String> vector1 = getVector();//some function which return the Vector of type String
     if(vector1!=null){
           set1=new HashSet<String>(vactor1);
     }
     else{
           set1= new HashSet<String>();
     }
  }
}

Upvotes: 0

Views: 448

Answers (2)

ajb
ajb

Reputation: 31699

Your statement

private static final Set<String> set1 = getSet();

means this: It calls a method getSet, which it expects to return a value, and then it assigns the returned value into set1. (Note that it needs to be Set, not set.)

For this to work, getSet actually has to return a value, using the return statement. So instead of 

set1=new HashSet<String>(vactor1);

the statement should be

return new HashSet<String>(vector1);  // make sure vector1 is spelled correctly

and similarly with the other set1= statement in getSet.

Upvotes: 1

Maroun
Maroun

Reputation: 95968

private static final set<String> set1 = getSet();

set1 is final, meaning that it cannot be changed.

However,

set1=new HashSet<String>(vactor1);

and

set1= new HashSet<String>();

are trying to change it. See JLS 4.12.4. final Variables:

A variable can be declared final. A final variable may only be assigned to once. Declaring a variable final can serve as useful documentation that its value will not change and can help avoid programming errors.

It is a compile-time error if a final variable is assigned to unless it is definitely unassigned (§16) immediately prior to the assignment.

I don't know if it's a typo or not, but static should be all lower-case, not Static.

Upvotes: 3

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