Question

In Java’s String.class, I see this

public String substring(int beginIndex, int endIndex){
   //if statements
   return ((beginIndex == 0) && (endIndex == count)) ? this:
     new String (offset + beginIndex, endIndex - beginIndex, value);
}

What is the ‘?’ doing? While we’re on the subject, can anyone explain whats happening with that ‘new String’ in the return statement? Is that some kind of conditional?

Answer 1

It’s a ternary operator and it is equivalent to:

if((beginIndex == 0) && (endIndex == count)) {
  return this;
} else { 
  return new String (offset + beginIndex, endIndex - beginIndex, value);
}