Common string methods in Java - Cheat Sheet & Quick Revision

overview

Recall & Review

beginner

What does the length() method do in a Java String?

It returns the number of characters in the string, including spaces and special characters.

beginner

How does the toUpperCase() method affect a string?

It creates a new string where all letters are converted to uppercase. The original string stays the same.

intermediate

What is the purpose of the substring(int beginIndex, int endIndex) method?

It extracts a part of the string starting at beginIndex and ending just before endIndex, returning that part as a new string.

beginner

Explain what equals(String anotherString) does.

It checks if two strings have exactly the same characters in the same order and returns true if they do, otherwise false.

beginner

What does the trim() method do to a string?

It removes any whitespace at the start and end of the string but does not change spaces inside the string.

Which method returns the number of characters in a Java string?

A size()

B length()

C count()

D getLength()

What does toLowerCase() do to a string?

A Converts all letters to lowercase

B Removes spaces

C Checks if string is lowercase

D Changes the original string

How do you get a part of a string from index 2 to 5 (exclusive) in Java?

A substring(2, 5)

B slice(2, 5)

C substr(2, 5)

D part(2, 5)

Which method compares two strings for exact equality?

A compare()

B match()

C equals()

D == operator

What does the trim() method remove from a string?

A All spaces inside the string

B All whitespace characters everywhere

C Tabs inside the string only

D Spaces at the start and end only

Describe five common string methods in Java and what each one does.

Explain how you would extract a substring and compare two strings for equality in Java.