What is the output of `System.out.println(“Hello” + 1 + 2)`?

The output of `System.out.println("Hello" + 1 + 2)` is "Hello12" because Java concatenates strings from left to right. In this case, "Hello" is concatenated with the integer 1 to form "Hello1", which is then concatenated with the integer 2 to produce "Hello12".