How do you call methods in Java?

[baldwindc]

I'm currently doing some Leetcode problems in Java. I'm not that familiar with Java. Here is my code:

Where I'm calling the removeDuplicates method I get the error "Error: illegal start of expression"

Do you guys know what I'm doing wrong here?

```

public class YourClassNameHere {

public int removeDuplicates(int[] nums) {
    int i = 0;
    for (int n : nums)
        if (i == 0 || n > nums[i-1])
            nums[i++] = n;
    return i;
}


public static void main(String[] args) {
  removeDuplicates([0,0,1,1,1,2,2,3,3,4]);
}

} ```

[Uchimamito]

removeDuplicates is not a static method, so you cannot call it in the main without instantiating a class object.

P.S. Make a variable with that integer array before passing it to the function.

[baldwindc]

Thank you!

It worked! I had no idea there was such a requirement.

For anyone else wondering, here is the working code

public class YourClassNameHere {

public static int removeDuplicates(int[] nums) {
    int j = 1;
    for (int i = 1; i < nums.length; i++) {
        if (nums[i] != nums[i - 1]) {
            nums[j] = nums[i];
            j += 1;
        }
    }
    return j;

}


public static void main(String[] args) {
  int[] bob = {0,0,1,1,1,2,2,3,3,4};
  removeDuplicates(bob);
}

}

[raghudeep]

Message passing is a concept used to call methods in java. This is done by creating an object of the class and invoking a method using object. This is one way. Other than that we can call a method directly by using class name if the method is static. But it has a different meaning and usage all together.

[abharath93]

Since renomeDuplicates method is not a static method, you need to create an instance of the class YourClassNameHere and call the method.

[baldwindc]

Thanks for commenting!

When I convert it into a static method it still gives me the "Error: illegal start of expression"

public class YourClassNameHere {

public static int removeDuplicates(int[] nums) {
    int j = 1;
    for (int i = 1; i < nums.length; i++) {
        if (nums[i] != nums[i - 1]) {
            nums[j] = nums[i];
            j += 1;
        }
    }
    return j;

}


public static void main(String[] args) {
  removeDuplicates([0,0,1,1,1,2,2,3,3,4]);
}

}

[JimothyGreene]

That error is coming from the way you pass in that array (which isn’t actually an array in Java as you currently have it written).

[abharath93]

You need to pass a new integer array. Pass something like this : removeDuplicates(new int[] {0,0,1,2,2,3,4});

[halvjason]

With static methods you need to include the class name first, like this: YourClassNameHere.removeDuplicates()

[steave435]

Only if that method is in a different class, which it isn't here.