Question

Given the following declarations:

StringBuilder buffer = new StringBuilder(""Testing Testing"");
buffer.setLength(7);
buffer.ensureCapacity(5);
Which of the following is true?

a. buffer has capacity 5.
b. buffer has capacity 31.
c. buffer has content ""Testin"".
d. buffer has length 15."

Answer 1

The correct answer is c. buffer has content "Testin" after the setLength(7) method is called on the StringBuilder object. The ensureCapacity(5) method will not decrease the existing capacity. Option d.

Step-by-step explanation:

The student's question pertains to the behavior of the StringBuilder class in Java, specifically related to the methods setLength and ensureCapacity. Initially, a StringBuilder object is created with the content "Testing Testing". When setLength(7) is called, it modifies the length of the content to the first 7 characters, which makes the content of the buffer "Testin". The ensureCapacity(5) method ensures that the buffer has at least the capacity to hold 5 characters, but since the buffer already has a capacity greater than 5, this call will not decrease its capacity. Therefore, the correct answer is c. buffer has content "Testin". Moreover, after calling setLength(7), the buffer's length is now 7, as it has been truncated.