Prime Number test beginner Java

College assignment for testing a positive number (called num) is a Prime Number or not.
I must use a Do while loop
Ive attempted the code as follows but its failing the test

public class Primes {
public static main void (String args[]){
int num = 1;
int 2 = 0;
boolean flag = false;
do {
if (num%i == 1) {
flag = true;
break:
}
num ++

while (i<=num);
{
if (flag = true);
{
System.out.println (num + "is a prime number ");
}
else
{
System.out.prinln (num + "is not a prime number ");
}
}
}
}

1. Main function signature

it should be

public static void main(String args[])

not

public static main void (String args[])

2. you cannot start a variable name with a number

int 2 = 0;

you probably mean

int i = 0;

3. do { ... } while(...);

The format of a do while loop is

do {
  something();
} while (condition);

4. Semicolon means end of statement

while (condition); {
  something();
}

in this case something() is not in your while loop

5. Watch out for assignment in if

if (flag = true)

this is assigning flag to true. And the condition is always true (since the resulting of the assignment is true).

6. Not System.out.prinln

It is System.out.println. Use an IDE.

Final solution

public class Primes {
    public static void main(String args[]) {
        int num = 3;
        int i = 2;
        boolean flag = false;
        do {
            if (num % i == 0) {
                flag = true;
                break;
            }
            i++;
        } while (i < num);
        if (!flag) {
            System.out.println(num + " is a prime number ");
        } else {
            System.out.println(num + " is not a prime number ");
        }
    }
}

I also fixed some logical problem such as

1. you should probably increment i instead of num,
2. while (i < num) instead of while (i<=num), otherwise some (last) i always equals to num, making everything not a prime
3. a number is not a prime when flag is true. you should probably invert the if logic. Flag is true when you find something that is evenly divisible, meaning the number is not a prime.

There are better solutions, but I stick with your format.

You have a couple of different issues:

Firstly, it should be:

public static void main(String[] args){

Second, your variable on line 4 doesn't have name.

Your format for your do while statement is also, not quite right.

Another poster has a good example of a do while loop here:
https://stackoverflow.com/questions/28663628/do-while-loop-java-explanation

Also, go over the rules for where semicolons should be placed.