SCJP Java String Handling and Regular Expressions 5

Question 1

What is the result of `"ABC".compareToIgnoreCase("abc")`?

Accepted Answer

0

Answer

`compareToIgnoreCase` returns 0 when the two strings are equal ignoring case.

Question 2

Which regex quantifier means 'one or more, possessive (no backtracking)'?

Accepted Answer

"+" (possessive: `++`)

Answer

The possessive quantifier `++` matches one or more characters without giving them back during backtracking.

Question 3

What does calling `StringBuffer.reverse()` on the buffer `"12345"` produce?

Accepted Answer

"54321"

Answer

`StringBuffer.reverse()` reverses the character sequence in place and returns the same `StringBuffer`.

Question 4

Which `String` method splits the string `"a,b,,c"` using `","` as delimiter, keeping trailing empty strings?

Accepted Answer

split(",", -1)

Answer

Passing a negative limit to `split` disables the default behavior of discarding trailing empty strings.

Question 5

What is the output of `System.out.println(Pattern.matches("\d+", "123abc"));`?

Accepted Answer

false

Answer

`Pattern.matches` requires the entire input to match the pattern; "123abc" contains non-digit characters, so it returns `false`.

SCJP - Sun Certified Java Programmer Practice Test