Switch Case in Java – Learn How to Use Switch Statement

Java is a high-level, class-based, object-oriented programming language. In Java, switch statements provide a way to execute one block of source code, among many, based on the value of an expression. It is an alternative to multiple ‘if-else’ statements.

If there is a match, the associated block of code is executed. Switch case in Java is fall-through, which means it executes all the cases after the first match if a break statement is not encountered.

What is Switch Statement?

A switch statement in Java is a control flow statement that allows the execution of one block of source code among many based on the value of an expression. It provides a more efficient and readable way to handle multiple possible values for a variable, compared to using multiple ‘if-else’ statements. The ‘switch’ statement evaluates the expression provided and then matches its result with one of the ‘case’ labels defined within the ‘switch’ block.

The syntax of a switch statement in Java is as follows.

The following program demonstrates the switch statement.

Program

Output

Some Important Rules for Java Switch Statements

Here are some important rules for using switch statements in Java language.

• The case value must be constants or literals of the same type as the switch expression.
• Switch does not allow duplicate case values.
• The break statement is used to exit from the switch block. The break statement is optional, but It is recommended.
• The default case is also optional. It executes if no cases match the switch expression.

Also Read: Java Tutorial for Beginners

Features of Switch Statement

A Switch statement allows you to execute different source code blocks depending on the value of a variable or expression. Here are basic important aspects of a switch statement.

• Multiple Case Labels: We can have multiple ‘case’ labels within a ‘switch’ statement. Each ‘case’ corresponds to a specific value the ‘switch’ expression might take.

• Default Case: The ‘default’ label is optional but recommended. It provides a fallback option when none of the ‘case’ labels matches the ‘switch’ expression.

• Expression Support: Since Java 12, ‘switch’ supports expression syntax, allowing it to return a value. This new syntax makes ‘switch’ concise and expressive.

The break keyword

In the switch statement, we can also use the break statement keyword to come out of the switch block immediately with no further comparisons. This immediately transfers control to the statement following the loop. This is useful when you need to exit the switch comparison.

The following program demonstrates break keywords in Java.

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The default keyword

Java’s ‘default’ keyword in a ‘switch’ statement specifies a block of source code that is to be executed if none of the ‘case’ values match the expression ‘switch’. Much like an ‘else’ block of an ‘if-else’ statement, it works as a default or fallback action.

The following program demonstrates the default keyword in the switch.

Program

Output

Difference between switch and if-else statement

Here’s a comparison of Java’s ‘switch’ and ‘if-else’ statements.

Nested Switch Statement in Java

When a developer switch statement is placed inside another, it is called a nesting switch statement. This allows for more complex decision-making processes, where the outcome of one ‘switch’ statement can determine which nested ‘switch’ statement should be evaluated.

The following program demonstrates the nesting switch statement in Java language:

Program

Output

Also Read: Final Keyword in Java

Conclusion

In Java, the ‘switch’ statement provides a structured and efficient way to address several discrete values of an expression. The ‘switch’ statement evaluates an expression and passes control flow to the matching ‘case’ label, wherein the execution of the associated source code block is carried out.

Thus, the switch statement proves very helpful when dealing with a predefined set of values. Proper understanding and utilization of the ‘switch’ statement can significantly improve your source code’s readability and maintainability. The ‘switch’ statement, therefore, proves to be a very useful tool for developers in case they have to deal with multiple conditional branches based on a single expression.