Question

    StringBuilder str = new StringBuilder("Today");
    str.append(" is ").append("a").append(" sunny ").append(" day.");

In the java code above, I understand that first I created an object of type StringBuilder. Then I used the object reference str to access the method append of the class StringBuilder. After this, I loose track. Is the method append used after str.append(“is”) inside the append method, or am I calling the same method in this class? Further, can anyone explain the flow of execution of the above statement. Which of the above append methods is executed first?

Answer 1

str.append(" is ") returns the StringBuilder itself. You’re calling a method on the object returned by the method. It’s the same as doing

user.getAddress().getStreet().charAt(0);

Except in your code, each append() method call returns the same object, which allows chaining multiple method calls to the same StringBuilder.