CODEWITHSUNDEEP
javastaticreferencestacknon-static
1991DBA
1991DBA

Reputation: 805

Static reference to non-static field Java error

I'll preface this by saying that I've been a longtime fan of Stack Overflow, and over the past few semesters I've usually been able to find the answer to all my questions without actually asking one. However, I've been having problems with a stack program. There's more code than this, but I think I've narrowed my problem down to this one error. It states

Exception in thread "main" java.lang.Error: Unresolved compilation problems:

Cannot make a static reference to the non-static field Stack1
The constructor Stack(int) is undefined

at stack.main(stack.java:11)

Can anyone explain what the issue might be? Or better yet, point me to somewhere that will explain it? I've tried looking it up on Overflow and through google, but I think a combination of not knowing what I'm actually looking for and/or fatigue is preventing me from finding a concrete answer. Thanks for any help in advance.

public class stack {
private Object[] Stack1;
private int topOfStack;
private int max;
//private int empty;
//private int capacity;

public static void main(String[] args) {
Stack1 = new Stack(5);
    
}

public Stack(int size) {
    if (size < 0){
        throw new IllegalArgumentException("Parameter must be >0. Parameter was " + size + ".");
    }
    
    max = size; 
    Stack1 = (Object[]) (new Object[size]);
    topOfStack = -1;
}
   }

Upvotes: 2

Views: 3768

Answers (5)

Michael McGowan
Michael McGowan

Reputation: 6608

Stack1 is in instance variable to the stack class. In your static main method, you try to store a value in the Stack1 variable even though it is an instance variable. Also, you try to assign a non-array type to a variable whose type is an array of Object. Furthermore, you have a constructor for Stack (note the uppercase) even though the class is called stack in lowercase.

Upvotes: 0

Bhesh Gurung
Bhesh Gurung

Reputation: 51030

In the following line -

private Object[] Stack1;

Stack1 is not static.

And in the following you are trying to refer to Stack1 -

public static void main(String[] args) {
    Stack1 = new Stack(5);
}

from within main which is static.

Thus -

Cannot make a static reference to the non-static field Stack1

Your constructor name is Stack which does not match class name is stack. So -

The constructor Stack(int) is undefined

May be, you want to name your class Stack and in your main the following -

public static void main(String[] args) {
    Stack stack1 = new Stack(5);
}

Upvotes: 1

Snowy Coder Girl
Snowy Coder Girl

Reputation: 5518

Rename your class "Stack" (uppercase) and change the line:

Stack1 = new Stack(5)

to:

Stack stack1 = new Stack(5);

Upvotes: 1

Dave L.
Dave L.

Reputation: 11238

Keeping the lower case class declaration, I'm guessing the assignment 

   Stack1 = new Stack(5);

is not what you meant. Rather: 

Stack1 stack = new stack(5);

Upvotes: 0

K-ballo
K-ballo

Reputation: 81349

Your class is declared as stack lowercase.

Upvotes: 0

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