SCJP Java String Handling and Regular Expressions 2

Question 1

What is the output of: System.out.println("Java".toUpperCase());

Accepted Answer

JAVA

Answer

toUpperCase() converts every character in the string to its uppercase equivalent.

Question 2

What does String.valueOf(42) return?

Accepted Answer

"42" as a String

Answer

String.valueOf(int) converts the integer to its String representation, returning "42".

Question 3

Which regular expression pattern matches one or more digits?

Accepted Answer

\d+

Answer

The quantifier + means one or more, so \d+ matches one or more digit characters.

Question 4

What is the result of "  Hello  ".trim()?

Accepted Answer

"Hello"

Answer

trim() removes leading and trailing whitespace from both ends of the string.

Question 5

Which method of the Pattern class is used to compile a regular expression?

Accepted Answer

Pattern.compile()

Answer

Pattern.compile(String regex) compiles the given regular expression into a Pattern object.

SCJP - Sun Certified Java Programmer Practice Test