Learn Java from Scratch - A Beginner's Guide - Step 06 - String Concatenation and Join, Replace Methods

The video tutorial covers the concatenation operator in Java, explaining how it works with strings and numbers. It discusses the rules of concatenation, providing examples to illustrate the concept. The tutorial also introduces utility methods in the String class, such as join and replace, and offers guidance on exploring and understanding the String APIs. The importance of understanding the possibilities and operations available in the String class is emphasized, along with tips on using documentation to find the right methods.

What is the result of the expression '1' + 2 in Java?

• 3

• 12

• 21

• Error

How does Java evaluate the expression 1 + 2 + '3'?

• 33

• 123

• Error

• 6

What happens when you concatenate a string and an integer in Java?

• Subtraction

• Addition

• Multiplication

• Concatenation

Which method in the String class is used to join multiple strings with a delimiter?

• join

• merge

• concat

• append

What is the output of replacing 'AB' with 'XYZ' in the string 'ABCD'?

• CDXYZ

• ABXYZ

• XYZCD

• XYZAB

What is a recommended way to explore available methods in a Java class?

• Guess the method names

• Use Javadoc

• Memorize all methods

• Use trial and error

Why is it important to understand the possibilities of APIs rather than memorizing all methods?

• APIs are not useful

• APIs rarely change

• APIs have too many methods

• APIs are intuitive