Streamlining Exception Handling in Java
The Era of Code Redundancy
Before Java 7, developers had to write multiple exception handling codes for different types of exceptions, even if it meant duplicating code. Let’s consider an example. Suppose we have a program that may throw two exceptions: ArithmeticException and ArrayIndexOutOfBoundsException. To handle these exceptions, we would need to write separate catch blocks, resulting in duplicated code.
The Dawn of Multi-Catch Blocks
With the introduction of Java SE 7, the game changed. We can now catch multiple types of exceptions in a single catch block, reducing code duplication and increasing efficiency. This feature is made possible by using a vertical bar or pipe (|) to separate each exception type. For instance:
Example 2: Multi-Catch Block
The bytecode generated by this program is smaller and more efficient than its predecessor, thanks to the elimination of code redundancy.
Important Note
When handling multiple exceptions in a single catch block, the catch parameter is implicitly final, meaning we cannot assign new values to it.
Catching Base Exceptions
When dealing with a hierarchy of exceptions, we can simplify our code by catching the base exception instead of multiple specialized exceptions. This approach follows the rule of generalized to specialized. For example:
Example 3: Catching Base Exception Class Only
Since all exception classes are subclasses of the Exception class, we can catch the base exception and avoid catching multiple specialized exceptions.
Avoiding Compilation Errors
However, if we specify a base exception class in the catch block, we cannot use child exception classes in the same catch block. Doing so would result in a compilation error. Consider the following example:
Example 4: Catching Base and Child Exception Classes
In this case, we get a compilation error because ArithmeticException and ArrayIndexOutOfBoundsException are both subclasses of the Exception class.
By embracing the power of multi-catch blocks and catching base exceptions, we can write more efficient and streamlined code, making our lives as developers much easier.