This Java code snippet contains a for loop that has no body due to the semicolon at the end of the for statement. The loop itself will execute, initializing x to 0 and incrementing it while x is less than 3. On each iteration, the expression sum += ++x will be executed. It increments x before adding it to sum. The sequence of operations will be as follows: when x is 1, sum becomes 1; when x is 2, sum becomes 3; when x is 3, sum becomes 6. After the loop terminates because x is no longer less than 3, the single System.out.print statement outside the loop will execute, outputting the final value of sum prefixed with a dash. Therefore, the output is -6.