java – cannot make a static reference to the non-static field

java – cannot make a static reference to the non-static field

main is a static method. It cannot refer to balance, which is an attribute (non-static variable). balance has meaning only when it is referred through an object reference (such as myAccount.balance or yourAccount.balance). But it doesnt have any meaning when it is referred through class (such as Account.balance (whose balance is that?))

I made some changes to your code so that it compiles.

public static void main(String[] args) {
    Account account = new Account(1122, 20000, 4.5);
    account.withdraw(2500);
    account.deposit(3000);

and:

public void withdraw(double withdrawAmount) {
    balance -= withdrawAmount;
}

public void deposit(double depositAmount) {
    balance += depositAmount;
}   

the lines

account.withdraw(balance, 2500);
account.deposit(balance, 3000);

you might want to make withdraw and deposit non-static and let it modify the balance

public void withdraw(double withdrawAmount) {
    balance = balance - withdrawAmount;
}

public void deposit(double depositAmount) {
    balance = balance + depositAmount;
}   

and remove the balance parameter from the call

java – cannot make a static reference to the non-static field

The static calls to withdraw and deposit are your problem.
account.withdraw(balance, 2500);
This line cant work , since balance is an instance variable of Account. The code doesnt make much sense anyway, wouldnt withdraw/deposit be encapsulated inside the Account object itself? so the withdraw should be more like

public void withdraw(double withdrawAmount)
{
    balance -= withdrawAmount;
}

Of course depending on your problem you could do additional validation here to prevent negative balance etc.